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authorDavid Sommerseth <dazo@users.sourceforge.net>2010-07-22 22:30:27 +0200
committerDavid Sommerseth <dazo@users.sourceforge.net>2010-07-22 22:30:27 +0200
commitc70135d8ed31d133f2fb085bee01db8ad26d7fec (patch)
tree6b1edab6b87bd4c0d5b4aeca747232e524d28b36 /openvpn.8
parentAdded win/build_exe.py script, which is similar to (diff)
parentFixed client hang when server don't PUSH (aka the NO_SOUP_FOR_YOU patch) (diff)
downloadopenvpn-c70135d8ed31d133f2fb085bee01db8ad26d7fec.tar.xz
Merge branch 'bugfix2.1' into beta2.2
Conflicts: openvpn.8 - New option descriped (--register-dns) Signed-off-by: David Sommerseth <dazo@users.sourceforge.net>
Diffstat (limited to 'openvpn.8')
-rw-r--r--openvpn.81624
1 files changed, 815 insertions, 809 deletions
diff --git a/openvpn.8 b/openvpn.8
index 1aa8382..e13f74d 100644
--- a/openvpn.8
+++ b/openvpn.8
@@ -97,25 +97,25 @@ with a relatively lightweight footprint.
.SH OPTIONS
OpenVPN allows any option to be placed either on the command line
or in a configuration file. Though all command line options are preceded
-by a double-leading-dash ("--"), this prefix can be removed when
+by a double-leading-dash ("\-\-"), this prefix can be removed when
an option is placed in a configuration file.
.\"*********************************************************
.TP
-.B --help
+.B \-\-help
Show options.
.\"*********************************************************
.TP
-.B --config file
+.B \-\-config file
Load additional config options from
.B file
where each line corresponds to one command line option,
-but with the leading '--' removed.
+but with the leading '\-\-' removed.
If
-.B --config file
+.B \-\-config file
is the only option to the openvpn command,
the
-.B --config
+.B \-\-config
can be removed, and the command can be given as
.B openvpn file
@@ -187,25 +187,25 @@ secret static.key
.\"*********************************************************
.SS Tunnel Options:
.TP
-.B --mode m
+.B \-\-mode m
Set OpenVPN major mode. By default, OpenVPN runs in
point-to-point mode ("p2p"). OpenVPN 2.0 introduces
a new mode ("server") which implements a multi-client
server capability.
.\"*********************************************************
.TP
-.B --local host
+.B \-\-local host
Local host name or IP address for bind.
If specified, OpenVPN will bind to this address only.
If unspecified, OpenVPN will bind to all interfaces.
.\"*********************************************************
.TP
-.B --remote host [port] [proto]
+.B \-\-remote host [port] [proto]
Remote host name or IP address. On the client, multiple
-.B --remote
+.B \-\-remote
options may be specified for redundancy, each referring
to a different OpenVPN server. Specifying multiple
-.B --remote
+.B \-\-remote
options for this purpose is a special case of the more
general connection-profile feature. See the
.B <connection>
@@ -214,7 +214,7 @@ documentation below.
The OpenVPN client will try to connect to a server at
.B host:port
in the order specified by the list of
-.B --remote
+.B \-\-remote
options.
.B proto
@@ -229,18 +229,18 @@ one server.
Note that since UDP is connectionless, connection failure
is defined by the
-.B --ping
+.B \-\-ping
and
-.B --ping-restart
+.B \-\-ping-restart
options.
Note the following corner case: If you use multiple
-.B --remote
+.B \-\-remote
options, AND you are dropping root privileges on
the client with
-.B --user
+.B \-\-user
and/or
-.B --group,
+.B \-\-group,
AND the client is running a non-Windows OS, if the client needs
to switch to a different server, and that server pushes
back different TUN/TAP or route settings, the client may lack
@@ -248,7 +248,7 @@ the necessary privileges to close and reopen the TUN/TAP interface.
This could cause the client to exit with a fatal error.
If
-.B --remote
+.B \-\-remote
is unspecified, OpenVPN will listen
for packets from any IP address, but will not act on those packets unless
they pass all authentication tests. This requirement for authentication
@@ -257,7 +257,7 @@ trusted IP addresses (it is very easy to forge a source IP address on
a UDP packet).
When used in TCP mode,
-.B --remote
+.B \-\-remote
will act as a filter, rejecting connections from any host which does
not match
.B host.
@@ -283,7 +283,7 @@ and
An OpenVPN client will try each connection profile sequentially
until it achieves a successful connection.
-.B --remote-random
+.B \-\-remote-random
can be used to initially "scramble" the connection
list.
@@ -381,15 +381,15 @@ blocks below it.
.\"*********************************************************
.TP
-.B --remote-random
+.B \-\-remote-random
When multiple
-.B --remote
+.B \-\-remote
address/ports are specified, or if connection profiles are being
used, initially randomize the order of the list
as a kind of basic load-balancing measure.
.\"*********************************************************
.TP
-.B --proto p
+.B \-\-proto p
Use protocol
.B p
for communicating with remote host.
@@ -403,17 +403,17 @@ or
The default protocol is
.B udp
when
-.B --proto
+.B \-\-proto
is not specified.
For UDP operation,
-.B --proto udp
+.B \-\-proto udp
should be specified on both peers.
For TCP operation, one peer must use
-.B --proto tcp-server
+.B \-\-proto tcp-server
and the other must use
-.B --proto tcp-client.
+.B \-\-proto tcp-client.
A peer started with
.B tcp-server
will wait indefinitely for an incoming connection. A peer
@@ -421,9 +421,9 @@ started with
.B tcp-client
will attempt to connect, and if that fails, will sleep for 5
seconds (adjustable via the
-.B --connect-retry
+.B \-\-connect-retry
option) and try again infinite or up to N retries (adjustable via the
-.B --connect-retry-max
+.B \-\-connect-retry-max
option). Both TCP client and server will simulate
a SIGUSR1 restart signal if either side resets the connection.
@@ -443,9 +443,9 @@ application-level UDP protocols, or tunneling protocols which don't
possess a built-in reliability layer.
.\"*********************************************************
.TP
-.B --connect-retry n
+.B \-\-connect-retry n
For
-.B --proto tcp-client,
+.B \-\-proto tcp-client,
take
.B n
as the
@@ -453,16 +453,16 @@ number of seconds to wait
between connection retries (default=5).
.\"*********************************************************
.TP
-.B --connect-retry-max n
+.B \-\-connect-retry-max n
For
-.B --proto tcp-client,
+.B \-\-proto tcp-client,
take
.B n
as the
number of retries of connection attempt (default=infinite).
.\"*********************************************************
.TP
-.B --auto-proxy
+.B \-\-auto-proxy
Try to sense HTTP or SOCKS proxy settings automatically.
If no settings are present, a direct connection will be attempted.
If both HTTP and SOCKS settings are present, HTTP will be preferred.
@@ -474,7 +474,7 @@ InternetQueryOption API.
This option exists in OpenVPN 2.1 or higher.
.\"*********************************************************
.TP
-.B --http-proxy server port [authfile|'auto'|'auto-nct'] [auth-method]
+.B \-\-http-proxy server port [authfile|'auto'|'auto-nct'] [auth-method]
Connect to remote host through an HTTP proxy at address
.B server
and port
@@ -509,32 +509,32 @@ determine the authentication method, but to reject weak
authentication protocols such as HTTP Basic Authentication.
.\"*********************************************************
.TP
-.B --http-proxy-retry
+.B \-\-http-proxy-retry
Retry indefinitely on HTTP proxy errors. If an HTTP proxy error
occurs, simulate a SIGUSR1 reset.
.\"*********************************************************
.TP
-.B --http-proxy-timeout n
+.B \-\-http-proxy-timeout n
Set proxy timeout to
.B n
seconds, default=5.
.\"*********************************************************
.TP
-.B --http-proxy-option type [parm]
+.B \-\-http-proxy-option type [parm]
Set extended HTTP proxy options.
Repeat to set multiple options.
-.B VERSION version --
+.B VERSION version \-\-
Set HTTP version number to
.B version
(default=1.0).
-.B AGENT user-agent --
+.B AGENT user-agent \-\-
Set HTTP "User-Agent" string to
.B user-agent.
.\"*********************************************************
.TP
-.B --socks-proxy server [port]
+.B \-\-socks-proxy server [port]
Connect to remote host through a Socks5 proxy at address
.B server
and port
@@ -542,14 +542,14 @@ and port
(default=1080).
.\"*********************************************************
.TP
-.B --socks-proxy-retry
+.B \-\-socks-proxy-retry
Retry indefinitely on Socks proxy errors. If a Socks proxy error
occurs, simulate a SIGUSR1 reset.
.\"*********************************************************
.TP
-.B --resolv-retry n
+.B \-\-resolv-retry n
If hostname resolve fails for
-.B --remote,
+.B \-\-remote,
retry resolve for
.B n
seconds before failing.
@@ -559,18 +559,18 @@ Set
to "infinite" to retry indefinitely.
By default,
-.B --resolv-retry infinite
+.B \-\-resolv-retry infinite
is enabled. You can disable by setting n=0.
.\"*********************************************************
.TP
-.B --float
+.B \-\-float
Allow remote peer to change its IP address and/or port number, such as due to
DHCP (this is the default if
-.B --remote
+.B \-\-remote
is not used).
-.B --float
+.B \-\-float
when specified with
-.B --remote
+.B \-\-remote
allows an OpenVPN session to initially connect to a peer
at a known address, however if packets arrive from a new
address and pass all authentication tests, the new address
@@ -579,14 +579,14 @@ you are connecting to a peer which holds a dynamic address
such as a dial-in user or DHCP client.
Essentially,
-.B --float
+.B \-\-float
tells OpenVPN to accept authenticated packets
from any address, not only the address which was specified in the
-.B --remote
+.B \-\-remote
option.
.\"*********************************************************
.TP
-.B --ipchange cmd
+.B \-\-ipchange cmd
Execute shell command
.B cmd
when our remote ip-address is initially authenticated or
@@ -597,11 +597,11 @@ Execute as:
.B cmd ip_address port_number
Don't use
-.B --ipchange
+.B \-\-ipchange
in
-.B --mode server
+.B \-\-mode server
mode. Use a
-.B --client-connect
+.B \-\-client-connect
script instead.
See the "Environmental Variables" section below for
@@ -636,41 +636,41 @@ reestablish a connection with its most recently authenticated
peer on its new IP address.
.\"*********************************************************
.TP
-.B --port port
+.B \-\-port port
TCP/UDP port number for both local and remote. The current
default of 1194 represents the official IANA port number
assignment for OpenVPN and has been used since version 2.0-beta17.
Previous versions used port 5000 as the default.
.\"*********************************************************
.TP
-.B --lport port
+.B \-\-lport port
TCP/UDP port number for bind.
.\"*********************************************************
.TP
-.B --rport port
+.B \-\-rport port
TCP/UDP port number for remote.
.\"*********************************************************
.TP
-.B --bind
+.B \-\-bind
Bind to local address and port. This is the default unless any of
-.B --proto tcp-client
+.B \-\-proto tcp-client
,
-.B --http-proxy
+.B \-\-http-proxy
or
-.B --socks-proxy
+.B \-\-socks-proxy
are used.
.\"*********************************************************
.TP
-.B --nobind
+.B \-\-nobind
Do not bind to local address and port. The IP stack will allocate
a dynamic port for returning packets. Since the value of the dynamic port
could not be known in advance by a peer, this option is only suitable for
peers which will be initiating connections by using the
-.B --remote
+.B \-\-remote
option.
.\"*********************************************************
.TP
-.B --dev tunX | tapX | null
+.B \-\-dev tunX | tapX | null
TUN/TAP virtual network device (
.B X
can be omitted for a dynamic device.)
@@ -688,7 +688,7 @@ devices encapsulate IPv4 or IPv6 (OSI Layer 3) while
devices encapsulate Ethernet 802.3 (OSI Layer 2).
.\"*********************************************************
.TP
-.B --dev-type device-type
+.B \-\-dev-type device-type
Which device type are we using?
.B device-type
should be
@@ -698,60 +698,60 @@ or
.B tap
(OSI Layer 2).
Use this option only if the TUN/TAP device used with
-.B --dev
+.B \-\-dev
does not begin with
.B tun
or
.B tap.
.\"*********************************************************
.TP
-.B --topology mode
+.B \-\-topology mode
Configure virtual addressing topology when running in
-.B --dev tun
+.B \-\-dev tun
mode. This directive has no meaning in
-.B --dev tap
+.B \-\-dev tap
mode, which always uses a
.B subnet
topology.
If you set this directive on the server, the
-.B --server
+.B \-\-server
and
-.B --server-bridge
+.B \-\-server-bridge
directives will automatically push your chosen topology setting to clients
as well. This directive can also be manually pushed to clients. Like the
-.B --dev
+.B \-\-dev
directive, this directive must always be compatible between client and server.
.B mode
can be one of:
-.B net30 --
+.B net30 \-\-
Use a point-to-point topology, by allocating one /30 subnet per client.
This is designed to allow point-to-point semantics when some
or all of the connecting clients might be Windows systems. This is the
default on OpenVPN 2.0.
-.B p2p --
+.B p2p \-\-
Use a point-to-point topology where the remote endpoint of the client's
tun interface always points to the local endpoint of the server's tun interface.
This mode allocates a single IP address per connecting client.
Only use
when none of the connecting clients are Windows systems. This mode
is functionally equivalent to the
-.B --ifconfig-pool-linear
+.B \-\-ifconfig-pool-linear
directive which is available in OpenVPN 2.0 and is now deprecated.
-.B subnet --
+.B subnet \-\-
Use a subnet rather than a point-to-point topology by
configuring the tun interface with a local IP address and subnet mask,
similar to the topology used in
-.B --dev tap
+.B \-\-dev tap
and ethernet bridging mode.
This mode allocates a single IP address per connecting client and works on
Windows as well. Only available when server and clients are OpenVPN 2.1 or
higher, or OpenVPN 2.0.x which has been manually patched with the
-.B --topology
+.B \-\-topology
directive code. When used on Windows, requires version 8.2 or higher
of the TAP-Win32 driver. When used on *nix, requires that the tun
driver supports an
@@ -761,26 +761,26 @@ command which sets a subnet instead of a remote endpoint IP address.
This option exists in OpenVPN 2.1 or higher.
.\"*********************************************************
.TP
-.B --tun-ipv6
+.B \-\-tun-ipv6
Build a tun link capable of forwarding IPv6 traffic.
Should be used in conjunction with
-.B --dev tun
+.B \-\-dev tun
or
-.B --dev tunX.
+.B \-\-dev tunX.
A warning will be displayed
if no specific IPv6 TUN support for your OS has been compiled into OpenVPN.
.\"*********************************************************
.TP
-.B --dev-node node
+.B \-\-dev-node node
Explicitly set the device node rather than using
/dev/net/tun, /dev/tun, /dev/tap, etc. If OpenVPN
cannot figure out whether
.B node
is a TUN or TAP device based on the name, you should
also specify
-.B --dev-type tun
+.B \-\-dev-type tun
or
-.B --dev-type tap.
+.B \-\-dev-type tap.
On Windows systems, select the TAP-Win32 adapter which
is named
@@ -788,24 +788,24 @@ is named
in the Network Connections Control Panel or the
raw GUID of the adapter enclosed by braces.
The
-.B --show-adapters
+.B \-\-show-adapters
option under Windows can also be used
to enumerate all available TAP-Win32
adapters and will show both the network
connections control panel name and the GUID for
each TAP-Win32 adapter.
.TP
-.B --lladdr address
+.B \-\-lladdr address
Specify the link layer address, more commonly known as the MAC address.
Only applied to TAP devices.
.\"*********************************************************
.TP
-.B --iproute cmd
+.B \-\-iproute cmd
Set alternate command to execute instead of default iproute2 command.
May be used in order to execute OpenVPN in unprivileged environment.
.\"*********************************************************
.TP
-.B --ifconfig l rn
+.B \-\-ifconfig l rn
Set TUN/TAP adapter parameters.
.B l
is the IP address of the local VPN endpoint.
@@ -820,7 +820,7 @@ which is being created or connected to.
For TUN devices, which facilitate virtual
point-to-point IP connections,
the proper usage of
-.B --ifconfig
+.B \-\-ifconfig
is to use two private IP addresses
which are not a member of any
existing subnet which is in use.
@@ -834,7 +834,7 @@ you will be pinging across the VPN.
For TAP devices, which provide
the ability to create virtual
ethernet segments,
-.B --ifconfig
+.B \-\-ifconfig
is used to set an IP address and
subnet mask just as a physical
ethernet adapter would be
@@ -855,42 +855,42 @@ standard interface to the different
ifconfig implementations on different
platforms.
-.B --ifconfig
+.B \-\-ifconfig
parameters which are IP addresses can
also be specified as a DNS or /etc/hosts
file resolvable name.
For TAP devices,
-.B --ifconfig
+.B \-\-ifconfig
should not be used if the TAP interface will be
getting an IP address lease from a DHCP
server.
.\"*********************************************************
.TP
-.B --ifconfig-noexec
+.B \-\-ifconfig-noexec
Don't actually execute ifconfig/netsh commands, instead
pass
-.B --ifconfig
+.B \-\-ifconfig
parameters to scripts using environmental variables.
.\"*********************************************************
.TP
-.B --ifconfig-nowarn
+.B \-\-ifconfig-nowarn
Don't output an options consistency check warning
if the
-.B --ifconfig
+.B \-\-ifconfig
option on this side of the
connection doesn't match the remote side. This is useful
when you want to retain the overall benefits of the
options consistency check (also see
-.B --disable-occ
+.B \-\-disable-occ
option) while only disabling the ifconfig component of
the check.
For example,
if you have a configuration where the local host uses
-.B --ifconfig
+.B \-\-ifconfig
but the remote host does not, use
-.B --ifconfig-nowarn
+.B \-\-ifconfig-nowarn
on the local host.
This option will also silence warnings about potential
@@ -898,7 +898,7 @@ address conflicts which occasionally annoy more experienced
users by triggering "false positive" warnings.
.\"*********************************************************
.TP
-.B --route network/IP [netmask] [gateway] [metric]
+.B \-\-route network/IP [netmask] [gateway] [metric]
Add route to routing table after connection is established.
Multiple routes can be specified. Routes will be
automatically torn down in reverse order prior to
@@ -912,20 +912,20 @@ while at the same time providing portable semantics
across OpenVPN's platform space.
.B netmask
-default -- 255.255.255.255
+default \-\- 255.255.255.255
.B gateway
-default -- taken from
-.B --route-gateway
+default \-\- taken from
+.B \-\-route-gateway
or the second parameter to
-.B --ifconfig
+.B \-\-ifconfig
when
-.B --dev tun
+.B \-\-dev tun
is specified.
.B metric
-default -- taken from
-.B --route-metric
+default \-\- taken from
+.B \-\-route-metric
otherwise 0.
The default can be specified by leaving an option blank or setting
@@ -940,37 +940,37 @@ also be specified as a DNS or /etc/hosts
file resolvable name, or as one of three special keywords:
.B vpn_gateway
--- The remote VPN endpoint address
+\-\- The remote VPN endpoint address
(derived either from
-.B --route-gateway
+.B \-\-route-gateway
or the second parameter to
-.B --ifconfig
+.B \-\-ifconfig
when
-.B --dev tun
+.B \-\-dev tun
is specified).
.B net_gateway
--- The pre-existing IP default gateway, read from the routing
+\-\- The pre-existing IP default gateway, read from the routing
table (not supported on all OSes).
.B remote_host
--- The
-.B --remote
+\-\- The
+.B \-\-remote
address if OpenVPN is being run in client mode, and is undefined in server mode.
.\"*********************************************************
.TP
-.B --max-routes n
+.B \-\-max-routes n
Allow a maximum number of n
-.B --route
+.B \-\-route
options to be specified, either in the local configuration file,
or pulled from an OpenVPN server. By default, n=100.
.\"*********************************************************
.TP
-.B --route-gateway gw|'dhcp'
+.B \-\-route-gateway gw|'dhcp'
Specify a default gateway
.B gw
for use with
-.B --route.
+.B \-\-route.
If
.B dhcp
@@ -979,14 +979,14 @@ the gateway address will be extracted from a DHCP
negotiation with the OpenVPN server-side LAN.
.\"*********************************************************
.TP
-.B --route-metric m
+.B \-\-route-metric m
Specify a default metric
.B m
for use with
-.B --route.
+.B \-\-route.
.\"*********************************************************
.TP
-.B --route-delay [n] [w]
+.B \-\-route-delay [n] [w]
Delay
.B n
seconds (default=0) after connection
@@ -994,16 +994,16 @@ establishment, before adding routes. If
.B n
is 0, routes will be added immediately upon connection
establishment. If
-.B --route-delay
+.B \-\-route-delay
is omitted, routes will be added immediately after TUN/TAP device
open and
-.B --up
+.B \-\-up
script execution, before any
-.B --user
+.B \-\-user
or
-.B --group
+.B \-\-group
privilege downgrade (or
-.B --chroot
+.B \-\-chroot
execution.)
This option is designed to be useful in scenarios where DHCP is
@@ -1012,18 +1012,18 @@ tap adapter addresses. The delay will give the DHCP handshake
time to complete before routes are added.
On Windows,
-.B --route-delay
+.B \-\-route-delay
tries to be more intelligent by waiting
.B w
seconds (w=30 by default)
for the TAP-Win32 adapter to come up before adding routes.
.\"*********************************************************
.TP
-.B --route-up cmd
+.B \-\-route-up cmd
Execute shell command
.B cmd
after routes are added, subject to
-.B --route-delay.
+.B \-\-route-delay.
See the "Environmental Variables" section below for
additional parameters passed as environmental variables.
@@ -1033,17 +1033,17 @@ Note that
can be a shell command with multiple arguments.
.\"*********************************************************
.TP
-.B --route-noexec
+.B \-\-route-noexec
Don't add or remove routes automatically. Instead pass routes to
-.B --route-up
+.B \-\-route-up
script using environmental variables.
.\"*********************************************************
.TP
-.B --route-nopull
+.B \-\-route-nopull
When used with
-.B --client
+.B \-\-client
or
-.B --pull,
+.B \-\-pull,
accept options pushed by server EXCEPT for routes.
When used on the client, this option effectively bars the
@@ -1052,16 +1052,16 @@ however note that this option still allows the server
to set the TCP/IP properties of the client's TUN/TAP interface.
.\"*********************************************************
.TP
-.B --allow-pull-fqdn
+.B \-\-allow-pull-fqdn
Allow client to pull DNS names from server (rather than being limited
to IP address) for
-.B --ifconfig,
-.B --route,
+.B \-\-ifconfig,
+.B \-\-route,
and
-.B --route-gateway.
+.B \-\-route-gateway.
.\"*********************************************************
.TP
-.B --redirect-gateway flags...
+.B \-\-redirect-gateway flags...
(Experimental) Automatically execute routing commands to cause all outgoing IP traffic
to be redirected over the VPN.
@@ -1069,7 +1069,7 @@ This option performs three steps:
.B (1)
Create a static route for the
-.B --remote
+.B \-\-remote
address which forwards to the pre-existing default gateway.
This is done so that
.B (3)
@@ -1080,11 +1080,11 @@ Delete the default gateway route.
.B (3)
Set the new default gateway to be the VPN endpoint address (derived either from
-.B --route-gateway
+.B \-\-route-gateway
or the second parameter to
-.B --ifconfig
+.B \-\-ifconfig
when
-.B --dev tun
+.B \-\-dev tun
is specified).
When the tunnel is torn down, all of the above steps are reversed so
@@ -1092,7 +1092,7 @@ that the original default route is restored.
Option flags:
-.B local --
+.B local \-\-
Add the
.B local
flag if both OpenVPN servers are directly connected via a common subnet,
@@ -1102,19 +1102,19 @@ flag will cause step
.B 1
above to be omitted.
-.B def1 --
+.B def1 \-\-
Use this flag to override
the default gateway by using 0.0.0.0/1 and 128.0.0.0/1
rather than 0.0.0.0/0. This has the benefit of overriding
but not wiping out the original default gateway.
-.B bypass-dhcp --
+.B bypass-dhcp \-\-
Add a direct route to the DHCP server (if it is non-local) which
bypasses the tunnel
(Available on Windows clients, may not be available
on non-Windows clients).
-.B bypass-dns --
+.B bypass-dns \-\-
Add a direct route to the DNS server(s) (if they are non-local) which
bypasses the tunnel
(Available on Windows clients, may not be available
@@ -1123,13 +1123,13 @@ on non-Windows clients).
Using the def1 flag is highly recommended.
.\"*********************************************************
.TP
-.B --link-mtu n
+.B \-\-link-mtu n
Sets an upper bound on the size of UDP packets which are sent
between OpenVPN peers. It's best not to set this parameter unless
you know what you're doing.
.\"*********************************************************
.TP
-.B --tun-mtu n
+.B \-\-tun-mtu n
Take the TUN device MTU to be
.B n
and derive the link MTU
@@ -1145,17 +1145,17 @@ MTU problems often manifest themselves as connections which
hang during periods of active usage.
It's best to use the
-.B --fragment
+.B \-\-fragment
and/or
-.B --mssfix
+.B \-\-mssfix
options to deal with MTU sizing issues.
.\"*********************************************************
.TP
-.B --tun-mtu-extra n
+.B \-\-tun-mtu-extra n
Assume that the TUN/TAP device might return as many as
.B n
bytes more than the
-.B --tun-mtu
+.B \-\-tun-mtu
size on read. This parameter defaults to 0, which is sufficient for
most TUN devices. TAP devices may introduce additional overhead in excess
of the MTU size, and a setting of 32 is the default when TAP devices are used.
@@ -1163,34 +1163,34 @@ This parameter only controls internal OpenVPN buffer sizing,
so there is no transmission overhead associated with using a larger value.
.\"*********************************************************
.TP
-.B --mtu-disc type
+.B \-\-mtu-disc type
Should we do Path MTU discovery on TCP/UDP channel? Only supported on OSes such
as Linux that supports the necessary system call to set.
.B 'no'
--- Never send DF (Don't Fragment) frames
+\-\- Never send DF (Don't Fragment) frames
.br
.B 'maybe'
--- Use per-route hints
+\-\- Use per-route hints
.br
.B 'yes'
--- Always DF (Don't Fragment)
+\-\- Always DF (Don't Fragment)
.br
.\"*********************************************************
.TP
-.B --mtu-test
+.B \-\-mtu-test
To empirically measure MTU on connection startup,
add the
-.B --mtu-test
+.B \-\-mtu-test
option to your configuration.
OpenVPN will send ping packets of various sizes
to the remote peer and measure the largest packets
which were successfully received. The
-.B --mtu-test
+.B \-\-mtu-test
process normally takes about 3 minutes to complete.
.\"*********************************************************
.TP
-.B --fragment max
+.B \-\-fragment max
Enable internal datagram fragmentation so
that no UDP datagrams are sent which
are larger than
@@ -1200,24 +1200,24 @@ bytes.
The
.B max
parameter is interpreted in the same way as the
-.B --link-mtu
+.B \-\-link-mtu
parameter, i.e. the UDP packet size after encapsulation
overhead has been added in, but not including
the UDP header itself.
The
-.B --fragment
+.B \-\-fragment
option only makes sense when you are using the UDP protocol (
-.B --proto udp
+.B \-\-proto udp
).
-.B --fragment
+.B \-\-fragment
adds 4 bytes of overhead per datagram.
See the
-.B --mssfix
+.B \-\-mssfix
option below for an important related option to
-.B --fragment.
+.B \-\-fragment.
It should also be noted that this option is not meant to replace
UDP fragmentation at the IP stack level. It is only meant as a
@@ -1230,44 +1230,45 @@ internal fragmentation capability may be your only option, such
as tunneling a UDP multicast stream which requires fragmentation.
.\"*********************************************************
.TP
-.B --mssfix max
+.B \-\-mssfix max
Announce to TCP sessions running over the tunnel that they should limit
their send packet sizes such that after OpenVPN has encapsulated them,
the resulting UDP packet size that OpenVPN sends to its peer will not
exceed
.B max
-bytes.
+bytes. The default value is
+.B 1450.
The
.B max
parameter is interpreted in the same way as the
-.B --link-mtu
+.B \-\-link-mtu
parameter, i.e. the UDP packet size after encapsulation
overhead has been added in, but not including
the UDP header itself.
The
-.B --mssfix
+.B \-\-mssfix
option only makes sense when you are using the UDP protocol
for OpenVPN peer-to-peer communication, i.e.
-.B --proto udp.
+.B \-\-proto udp.
-.B --mssfix
+.B \-\-mssfix
and
-.B --fragment
+.B \-\-fragment
can be ideally used together, where
-.B --mssfix
+.B \-\-mssfix
will try to keep TCP from needing
packet fragmentation in the first place,
and if big packets come through anyhow
(from protocols other than TCP),
-.B --fragment
+.B \-\-fragment
will internally fragment them.
Both
-.B --fragment
+.B \-\-fragment
and
-.B --mssfix
+.B \-\-mssfix
are designed to work around cases where Path MTU discovery
is broken on the network path between OpenVPN peers.
@@ -1276,35 +1277,35 @@ connection which successfully starts, but then stalls
during active usage.
If
-.B --fragment
+.B \-\-fragment
and
-.B --mssfix
+.B \-\-mssfix
are used together,
-.B --mssfix
+.B \-\-mssfix
will take its default
.B max
parameter from the
-.B --fragment max
+.B \-\-fragment max
option.
Therefore, one could lower the maximum UDP packet size
to 1300 (a good first try for solving MTU-related
connection problems) with the following options:
-.B --tun-mtu 1500 --fragment 1300 --mssfix
+.B \-\-tun-mtu 1500 \-\-fragment 1300 \-\-mssfix
.\"*********************************************************
.TP
-.B --sndbuf size
+.B \-\-sndbuf size
Set the TCP/UDP socket send buffer size.
Currently defaults to 65536 bytes.
.\"*********************************************************
.TP
-.B --rcvbuf size
+.B \-\-rcvbuf size
Set the TCP/UDP socket receive buffer size.
Currently defaults to 65536 bytes.
.\"*********************************************************
.TP
-.B --socket-flags flags...
+.B \-\-socket-flags flags...
Apply the given flags to the OpenVPN transport socket.
Currently, only
.B TCP_NODELAY
@@ -1321,12 +1322,12 @@ This option is pushable from server to client, and should be used
on both client and server for maximum effect.
.\"*********************************************************
.TP
-.B --txqueuelen n
+.B \-\-txqueuelen n
(Linux only) Set the TX queue length on the TUN/TAP interface.
Currently defaults to 100.
.\"*********************************************************
.TP
-.B --shaper n
+.B \-\-shaper n
Limit bandwidth of outgoing tunnel data to
.B n
bytes per second on the TCP/UDP port.
@@ -1362,7 +1363,7 @@ OpenVPN allows
to be between 100 bytes/sec and 100 Mbytes/sec.
.\"*********************************************************
.TP
-.B --inactive n [bytes]
+.B \-\-inactive n [bytes]
Causes OpenVPN to exit after
.B n
seconds of inactivity on the TUN/TAP device. The time length
@@ -1376,18 +1377,18 @@ produces a combined in/out byte count that is less than
.B bytes.
.\"*********************************************************
.TP
-.B --ping n
+.B \-\-ping n
Ping remote over the TCP/UDP control channel
if no packets have been sent for at least
.B n
seconds (specify
-.B --ping
+.B \-\-ping
on both peers to cause ping packets to be sent in both directions since
OpenVPN ping packets are not echoed like IP ping packets).
When used in one of OpenVPN's secure modes (where
-.B --secret, --tls-server,
+.B \-\-secret, \-\-tls-server,
or
-.B --tls-client
+.B \-\-tls-client
is specified), the ping packet
will be cryptographically secure.
@@ -1400,33 +1401,33 @@ pass will not time out.
(2) To provide a basis for the remote to test the existence
of its peer using the
-.B --ping-exit
+.B \-\-ping-exit
option.
.\"*********************************************************
.TP
-.B --ping-exit n
+.B \-\-ping-exit n
Causes OpenVPN to exit after
.B n
seconds pass without reception of a ping
or other packet from remote.
This option can be combined with
-.B --inactive, --ping,
+.B \-\-inactive, \-\-ping,
and
-.B --ping-exit
+.B \-\-ping-exit
to create a two-tiered inactivity disconnect.
For example,
-.B openvpn [options...] --inactive 3600 --ping 10 --ping-exit 60
+.B openvpn [options...] \-\-inactive 3600 \-\-ping 10 \-\-ping-exit 60
when used on both peers will cause OpenVPN to exit within 60
seconds if its peer disconnects, but will exit after one
hour if no actual tunnel data is exchanged.
.\"*********************************************************
.TP
-.B --ping-restart n
+.B \-\-ping-restart n
Similar to
-.B --ping-exit,
+.B \-\-ping-exit,
but trigger a
.B SIGUSR1
restart after
@@ -1445,13 +1446,13 @@ as
If the peer cannot be reached, a restart will be triggered, causing
the hostname used with
-.B --remote
+.B \-\-remote
to be re-resolved (if
-.B --resolv-retry
+.B \-\-resolv-retry
is also specified).
In server mode,
-.B --ping-restart, --inactive,
+.B \-\-ping-restart, \-\-inactive,
or any other type of internally generated signal will always be
applied to
individual client instance objects, never to whole server itself.
@@ -1460,14 +1461,14 @@ which would normally cause a restart, will cause the deletion
of the client instance object instead.
In client mode, the
-.B --ping-restart
+.B \-\-ping-restart
parameter is set to 120 seconds by default. This default will
hold until the client pulls a replacement value from the server, based on
the
-.B --keepalive
+.B \-\-keepalive
setting in the server configuration.
To disable the 120 second default, set
-.B --ping-restart 0
+.B \-\-ping-restart 0
on the client.
See the signals section below for more information
@@ -1477,27 +1478,27 @@ on
Note that the behavior of
.B SIGUSR1
can be modified by the
-.B --persist-tun, --persist-key, --persist-local-ip,
+.B \-\-persist-tun, \-\-persist-key, \-\-persist-local-ip,
and
-.B --persist-remote-ip
+.B \-\-persist-remote-ip
options.
Also note that
-.B --ping-exit
+.B \-\-ping-exit
and
-.B --ping-restart
+.B \-\-ping-restart
are mutually exclusive and cannot be used together.
.\"*********************************************************
.TP
-.B --keepalive n m
+.B \-\-keepalive n m
A helper directive designed to simplify the expression of
-.B --ping
+.B \-\-ping
and
-.B --ping-restart
+.B \-\-ping-restart
in server mode configurations.
For example,
-.B --keepalive 10 60
+.B \-\-keepalive 10 60
expands as follows:
.nf
@@ -1516,24 +1517,24 @@ expands as follows:
.fi
.\"*********************************************************
.TP
-.B --ping-timer-rem
+.B \-\-ping-timer-rem
Run the
-.B --ping-exit
+.B \-\-ping-exit
/
-.B --ping-restart
+.B \-\-ping-restart
timer only if we have a remote address. Use this option if you are
starting the daemon in listen mode (i.e. without an explicit
-.B --remote
+.B \-\-remote
peer), and you don't want to start clocking timeouts until a remote
peer connects.
.\"*********************************************************
.TP
-.B --persist-tun
+.B \-\-persist-tun
Don't close and reopen TUN/TAP device or run up/down scripts
across
.B SIGUSR1
or
-.B --ping-restart
+.B \-\-ping-restart
restarts.
.B SIGUSR1
@@ -1543,14 +1544,14 @@ but which offers finer-grained control over
reset options.
.\"*********************************************************
.TP
-.B --persist-key
+.B \-\-persist-key
Don't re-read key files across
.B SIGUSR1
or
-.B --ping-restart.
+.B \-\-ping-restart.
This option can be combined with
-.B --user nobody
+.B \-\-user nobody
to allow restarts triggered by the
.B SIGUSR1
signal.
@@ -1563,29 +1564,29 @@ This option solves the problem by persisting keys across
resets, so they don't need to be re-read.
.\"*********************************************************
.TP
-.B --persist-local-ip
+.B \-\-persist-local-ip
Preserve initially resolved local IP address and port number
across
.B SIGUSR1
or
-.B --ping-restart
+.B \-\-ping-restart
restarts.
.\"*********************************************************
.TP
-.B --persist-remote-ip
+.B \-\-persist-remote-ip
Preserve most recently authenticated remote IP address and port number
across
.B SIGUSR1
or
-.B --ping-restart
+.B \-\-ping-restart
restarts.
.\"*********************************************************
.TP
-.B --mlock
+.B \-\-mlock
Disable paging by calling the POSIX mlockall function.
Requires that OpenVPN be initially run as root (though
OpenVPN can subsequently downgrade its UID using the
-.B --user
+.B \-\-user
option).
Using this option ensures that key material and tunnel
@@ -1597,33 +1598,33 @@ would not be able to scan the system swap file to
recover previously used
ephemeral keys, which are used for a period of time
governed by the
-.B --reneg
+.B \-\-reneg
options (see below), then are discarded.
The downside
of using
-.B --mlock
+.B \-\-mlock
is that it will reduce the amount of physical
memory available to other applications.
.\"*********************************************************
.TP
-.B --up cmd
+.B \-\-up cmd
Shell command to run after successful TUN/TAP device open
(pre
-.B --user
+.B \-\-user
UID change). The up script is useful for specifying route
commands which route IP traffic destined for
private subnets which exist at the other
end of the VPN connection into the tunnel.
For
-.B --dev tun
+.B \-\-dev tun
execute as:
.B cmd tun_dev tun_mtu link_mtu ifconfig_local_ip ifconfig_remote_ip [ init | restart ]
For
-.B --dev tap
+.B \-\-dev tap
execute as:
.B cmd tap_dev tap_mtu link_mtu ifconfig_local_ip ifconfig_netmask [ init | restart ]
@@ -1648,62 +1649,62 @@ In this context, the last command line parameter passed to the script
will be
.I init.
If the
-.B --up-restart
+.B \-\-up-restart
option is also used, the up script will be called for restarts as
well. A restart is considered to be a partial reinitialization
of OpenVPN where the TUN/TAP instance is preserved (the
-.B --persist-tun
+.B \-\-persist-tun
option will enable such preservation). A restart
can be generated by a SIGUSR1 signal, a
-.B --ping-restart
+.B \-\-ping-restart
timeout, or a connection reset when the TCP protocol is enabled
with the
-.B --proto
+.B \-\-proto
option. If a restart occurs, and
-.B --up-restart
+.B \-\-up-restart
has been specified, the up script will be called with
.I restart
as the last parameter.
The following standalone example shows how the
-.B --up
+.B \-\-up
script can be called in both an initialization and restart context.
(NOTE: for security reasons, don't run the following example unless UDP port
9999 is blocked by your firewall. Also, the example will run indefinitely,
so you should abort with control-c).
-.B openvpn --dev tun --port 9999 --verb 4 --ping-restart 10 --up 'echo up' --down 'echo down' --persist-tun --up-restart
+.B openvpn \-\-dev tun \-\-port 9999 \-\-verb 4 \-\-ping-restart 10 \-\-up 'echo up' \-\-down 'echo down' \-\-persist-tun \-\-up-restart
Note that OpenVPN also provides the
-.B --ifconfig
+.B \-\-ifconfig
option to automatically ifconfig the TUN device,
eliminating the need to define an
-.B --up
+.B \-\-up
script, unless you also want to configure routes
in the
-.B --up
+.B \-\-up
script.
If
-.B --ifconfig
+.B \-\-ifconfig
is also specified, OpenVPN will pass the ifconfig local
and remote endpoints on the command line to the
-.B --up
+.B \-\-up
script so that they can be used to configure routes such as:
.B route add -net 10.0.0.0 netmask 255.255.255.0 gw $5
.\"*********************************************************
.TP
-.B --up-delay
+.B \-\-up-delay
Delay TUN/TAP open and possible
-.B --up
+.B \-\-up
script execution
until after TCP/UDP connection establishment with peer.
In
-.B --proto udp
+.B \-\-proto udp
mode, this option normally requires the use of
-.B --ping
+.B \-\-ping
to allow connection initiation to be sensed in the absence
of tunnel data, since UDP is a "connectionless" protocol.
@@ -1712,50 +1713,50 @@ transitioning to "connected" until connection establishment,
i.e. the receipt of the first authenticated packet from the peer.
.\"*********************************************************
.TP
-.B --down cmd
+.B \-\-down cmd
Shell command to run after TUN/TAP device close
(post
-.B --user
+.B \-\-user
UID change and/or
-.B --chroot
+.B \-\-chroot
). Called with the same parameters and environmental
variables as the
-.B --up
+.B \-\-up
option above.
Note that if you reduce privileges by using
-.B --user
+.B \-\-user
and/or
-.B --group,
+.B \-\-group,
your
-.B --down
+.B \-\-down
script will also run at reduced privilege.
.\"*********************************************************
.TP
-.B --down-pre
+.B \-\-down-pre
Call
-.B --down
+.B \-\-down
cmd/script before, rather than after, TUN/TAP close.
.\"*********************************************************
.TP
-.B --up-restart
+.B \-\-up-restart
Enable the
-.B --up
+.B \-\-up
and
-.B --down
+.B \-\-down
scripts to be called for restarts as well as initial program start.
This option is described more fully above in the
-.B --up
+.B \-\-up
option documentation.
.\"*********************************************************
.TP
-.B --setenv name value
+.B \-\-setenv name value
Set a custom environmental variable
.B name=value
to pass to script.
.\"*********************************************************
.TP
-.B --setenv FORWARD_COMPATIBLE 1
+.B \-\-setenv FORWARD_COMPATIBLE 1
Relax config file syntax checking so that unknown directives
will trigger a warning but not a fatal error,
on the assumption that a given unknown directive might be valid
@@ -1768,7 +1769,7 @@ new software features to gracefully degrade when encountered by
older software versions.
.\"*********************************************************
.TP
-.B --setenv-safe name value
+.B \-\-setenv-safe name value
Set a custom environmental variable
.B OPENVPN_name=value
to pass to script.
@@ -1779,23 +1780,23 @@ is a safety precaution to prevent a LD_PRELOAD style attack
from a malicious or compromised server.
.\"*********************************************************
.TP
-.B --script-security level [method]
+.B \-\-script-security level [method]
This directive offers policy-level control over OpenVPN's usage of external programs
and scripts. Lower
.B level
values are more restrictive, higher values are more permissive. Settings for
.B level:
-.B 0 --
+.B 0 \-\-
Strictly no calling of external programs.
.br
-.B 1 --
+.B 1 \-\-
(Default) Only call built-in executables such as ifconfig, ip, route, or netsh.
.br
-.B 2 --
+.B 2 \-\-
Allow calling of built-in executables and user-defined scripts.
.br
-.B 3 --
+.B 3 \-\-
Allow passwords to be passed to scripts via environmental variables (potentially unsafe).
The
@@ -1804,33 +1805,33 @@ parameter indicates how OpenVPN should call external commands and scripts.
Settings for
.B method:
-.B execve --
+.B execve \-\-
(default) Use execve() function on Unix family OSes and CreateProcess() on Windows.
.br
-.B system --
+.B system \-\-
Use system() function (deprecated and less safe since the external program command
line is subject to shell expansion).
The
-.B --script-security
+.B \-\-script-security
option was introduced in OpenVPN 2.1_rc9. For configuration file compatibility
with previous OpenVPN versions, use:
-.B --script-security 3 system
+.B \-\-script-security 3 system
.\"*********************************************************
.TP
-.B --disable-occ
+.B \-\-disable-occ
Don't output a warning message if option inconsistencies are detected between
peers. An example of an option inconsistency would be where one peer uses
-.B --dev tun
+.B \-\-dev tun
while the other peer uses
-.B --dev tap.
+.B \-\-dev tap.
Use of this option is discouraged, but is provided as
a temporary fix in situations where a recent version of OpenVPN must
connect to an old version.
.\"*********************************************************
.TP
-.B --user user
+.B \-\-user user
Change the user ID of the OpenVPN process to
.B user
after initialization, dropping privileges in the process.
@@ -1852,7 +1853,7 @@ you want to reset an OpenVPN daemon with a
signal
(for example in response
to a DHCP reset), you should make use of one or more of the
-.B --persist
+.B \-\-persist
options to ensure that OpenVPN doesn't need to execute any privileged
operations in order to restart (such as re-reading key files
or running
@@ -1860,16 +1861,16 @@ or running
on the TUN device).
.\"*********************************************************
.TP
-.B --group group
+.B \-\-group group
Similar to the
-.B --user
+.B \-\-user
option,
this option changes the group ID of the OpenVPN process to
.B group
after initialization.
.\"*********************************************************
.TP
-.B --cd dir
+.B \-\-cd dir
Change directory to
.B dir
prior to reading any files such as
@@ -1881,16 +1882,16 @@ to the current directory such as "." or "..".
This option is useful when you are running
OpenVPN in
-.B --daemon
+.B \-\-daemon
mode, and you want to consolidate all of
your OpenVPN control files in one location.
.\"*********************************************************
.TP
-.B --chroot dir
+.B \-\-chroot dir
Chroot to
.B dir
after initialization.
-.B --chroot
+.B \-\-chroot
essentially redefines
.B dir
as being the top
@@ -1909,22 +1910,22 @@ complications can result when scripts or restarts
are executed after the chroot operation.
.\"*********************************************************
.TP
-.B --setcon context
+.B \-\-setcon context
Apply SELinux
.B context
after initialization. This
essentially provides the ability to restrict OpenVPN's
rights to only network I/O operations, thanks to
SELinux. This goes further than
-.B --user
+.B \-\-user
and
-.B --chroot
+.B \-\-chroot
in that those two, while being great security features,
unfortunately do not protect against privilege escalation
by exploitation of a vulnerable system call. You can of
course combine all three, but please note that since
setcon requires access to /proc you will have to provide
-it inside the chroot directory (e.g. with mount --bind).
+it inside the chroot directory (e.g. with mount \-\-bind).
Since the setcon operation is delayed until after
initialization, OpenVPN can be restricted to just
@@ -1936,13 +1937,13 @@ allow many things required only during initialization.
Like with chroot, complications can result when scripts
or restarts are executed after the setcon operation,
which is why you should really consider using the
-.B --persist-key
+.B \-\-persist-key
and
-.B --persist-tun
+.B \-\-persist-tun
options.
.\"*********************************************************
.TP
-.B --daemon [progname]
+.B \-\-daemon [progname]
Become a daemon after all initialization functions are completed.
This option will cause all message and error output to
be sent to the syslog file (such as /var/log/messages),
@@ -1951,10 +1952,10 @@ ifconfig commands,
which will go to /dev/null unless otherwise redirected.
The syslog redirection occurs immediately at the point
that
-.B --daemon
+.B \-\-daemon
is parsed on the command line even though
the daemonization point occurs later. If one of the
-.B --log
+.B \-\-log
options is present, it will supercede syslog
redirection.
@@ -1970,7 +1971,7 @@ When unspecified,
defaults to "openvpn".
When OpenVPN is run with the
-.B --daemon
+.B \-\-daemon
option, it will try to delay daemonization until the majority of initialization
functions which are capable of generating fatal errors are complete. This means
that initialization scripts can test the return status of the
@@ -1980,20 +1981,20 @@ has correctly initialized and entered the packet forwarding event loop.
In OpenVPN, the vast majority of errors which occur after initialization are non-fatal.
.\"*********************************************************
.TP
-.B --syslog [progname]
+.B \-\-syslog [progname]
Direct log output to system logger, but do not become a daemon.
See
-.B --daemon
+.B \-\-daemon
directive above for description of
.B progname
parameter.
.\"*********************************************************
.TP
-.B --passtos
+.B \-\-passtos
Set the TOS field of the tunnel packet to what the payload's TOS is.
.\"*********************************************************
.TP
-.B --inetd [wait|nowait] [progname]
+.B \-\-inetd [wait|nowait] [progname]
Use this option when OpenVPN is being run from the inetd or
.BR xinetd(8)
server.
@@ -2004,7 +2005,7 @@ option must match what is specified in the inetd/xinetd
config file. The
.B nowait
mode can only be used with
-.B --proto tcp-server.
+.B \-\-proto tcp-server.
The default is
.B wait.
The
@@ -2016,16 +2017,16 @@ see the OpenVPN FAQ:
.I http://openvpn.net/faq.html#oneport
This option precludes the use of
-.B --daemon, --local,
+.B \-\-daemon, \-\-local,
or
-.B --remote.
+.B \-\-remote.
Note that this option causes message and error output to be handled in the same
way as the
-.B --daemon
+.B \-\-daemon
option. The optional
.B progname
parameter is also handled exactly as in
-.B --daemon.
+.B \-\-daemon.
Also note that in
.B wait
@@ -2035,7 +2036,7 @@ on using OpenVPN with xinetd:
.I http://openvpn.net/1xhowto.html
.\"*********************************************************
.TP
-.B --log file
+.B \-\-log file
Output logging messages to
.B file,
including output to stdout/stderr which
@@ -2046,44 +2047,44 @@ already exists it will be truncated.
This option takes effect
immediately when it is parsed in the command line
and will supercede syslog output if
-.B --daemon
+.B \-\-daemon
or
-.B --inetd
+.B \-\-inetd
is also specified.
This option is persistent over the entire course of
an OpenVPN instantiation and will not be reset by SIGHUP,
SIGUSR1, or
-.B --ping-restart.
+.B \-\-ping-restart.
Note that on Windows, when OpenVPN is started as a service,
logging occurs by default without the need to specify
this option.
.\"*********************************************************
.TP
-.B --log-append file
+.B \-\-log-append file
Append logging messages to
.B file.
If
.B file
does not exist, it will be created.
This option behaves exactly like
-.B --log
+.B \-\-log
except that it appends to rather
than truncating the log file.
.\"*********************************************************
.TP
-.B --suppress-timestamps
+.B \-\-suppress-timestamps
Avoid writing timestamps to log messages, even when they
otherwise would be prepended. In particular, this applies to
log messages sent to stdout.
.\"*********************************************************
.TP
-.B --writepid file
+.B \-\-writepid file
Write OpenVPN's main process ID to
.B file.
.\"*********************************************************
.TP
-.B --nice n
+.B \-\-nice n
Change process priority after initialization
(
.B n
@@ -2092,14 +2093,14 @@ greater than 0 is lower priority,
less than zero is higher priority).
.\"*********************************************************
.\".TP
-.\".B --nice-work n
+.\".B \-\-nice-work n
.\"Change priority of background TLS work thread. The TLS thread
.\"feature is enabled when OpenVPN is built
.\"with pthread support, and you are running OpenVPN
.\"in TLS mode (i.e. with
-.\".B --tls-client
+.\".B \-\-tls-client
.\"or
-.\".B --tls-server
+.\".B \-\-tls-server
.\"specified).
.\"
.\"Using a TLS thread offloads the CPU-intensive process of SSL/TLS-based
@@ -2109,12 +2110,12 @@ less than zero is higher priority).
.\"The parameter
.\".B n
.\"is interpreted exactly as with the
-.\".B --nice
+.\".B \-\-nice
.\"option above, but in relation to the work thread rather
.\"than the main thread.
.\"*********************************************************
.TP
-.B --fast-io
+.B \-\-fast-io
(Experimental) Optimize TUN/TAP/UDP I/O writes by avoiding
a call to poll/epoll/select prior to the write operation. The purpose
of such a call would normally be to block until the device
@@ -2125,13 +2126,13 @@ by avoiding the poll/epoll/select call, improving CPU efficiency
by 5% to 10%.
This option can only be used on non-Windows systems, when
-.B --proto udp
+.B \-\-proto udp
is specified, and when
-.B --shaper
+.B \-\-shaper
is NOT specified.
.\"*********************************************************
.TP
-.B --multihome
+.B \-\-multihome
Configure a multi-homed UDP server. This option can be used when
OpenVPN has been configured to listen on all interfaces, and will
attempt to bind client sessions to the interface on which packets
@@ -2140,13 +2141,13 @@ of the same interface. Note that this option is only relevant for
UDP servers and currently is only implemented on Linux.
Note: clients connecting to a
-.B --multihome
+.B \-\-multihome
server should always use the
-.B --nobind
+.B \-\-nobind
option.
.\"*********************************************************
.TP
-.B --echo [parms...]
+.B \-\-echo [parms...]
Echo
.B parms
to log output.
@@ -2155,7 +2156,7 @@ Designed to be used to send messages to a controlling application
which is receiving the OpenVPN log output.
.\"*********************************************************
.TP
-.B --remap-usr1 signal
+.B \-\-remap-usr1 signal
Control whether internally or externally
generated SIGUSR1 signals are remapped to
SIGHUP (restart without persisting state) or
@@ -2166,20 +2167,20 @@ can be set to "SIGHUP" or "SIGTERM". By default, no remapping
occurs.
.\"*********************************************************
.TP
-.B --verb n
+.B \-\-verb n
Set output verbosity to
.B n
(default=1). Each level shows all info from the previous levels.
Level 3 is recommended if you want a good summary
of what's happening without being swamped by output.
-.B 0 --
+.B 0 \-\-
No output except fatal errors.
.br
-.B 1 to 4 --
+.B 1 to 4 \-\-
Normal usage range.
.br
-.B 5 --
+.B 5 \-\-
Output
.B R
and
@@ -2187,12 +2188,12 @@ and
characters to the console for each packet read and write, uppercase is
used for TCP/UDP packets and lowercase is used for TUN/TAP packets.
.br
-.B 6 to 11 --
+.B 6 to 11 \-\-
Debug info range (see errlevel.h for additional
information on debug levels).
.\"*********************************************************
.TP
-.B --status file [n]
+.B \-\-status file [n]
Write operational status to
.B file
every
@@ -2204,21 +2205,21 @@ Status can also be written to the syslog by sending a
signal.
.\"*********************************************************
.TP
-.B --status-version [n]
+.B \-\-status-version [n]
Choose the status file format version number. Currently
.B n
can be 1, 2, or 3 and defaults to 1.
.\"*********************************************************
.TP
-.B --mute n
+.B \-\-mute n
Log at most
.B n
consecutive messages in the same category. This is useful to
limit repetitive logging of similar message types.
.\"*********************************************************
.TP
-.B --comp-lzo [mode]
-Use fast LZO compression -- may add up to 1 byte per
+.B \-\-comp-lzo [mode]
+Use fast LZO compression \-\- may add up to 1 byte per
packet for incompressible data.
.B mode
may be "yes", "no", or "adaptive" (default).
@@ -2228,16 +2229,16 @@ compression on or off for individual clients.
First, make sure the client-side config file enables selective
compression by having at least one
-.B --comp-lzo
+.B \-\-comp-lzo
directive, such as
-.B --comp-lzo no.
+.B \-\-comp-lzo no.
This will turn off compression by default,
but allow a future directive push from the server to
dynamically change the
on/off/adaptive setting.
Next in a
-.B --client-config-dir
+.B \-\-client-config-dir
file, specify the compression setting for the client,
for example:
@@ -2256,12 +2257,12 @@ setting for the server
side of the link, the second sets the client side.
.\"*********************************************************
.TP
-.B --comp-noadapt
+.B \-\-comp-noadapt
When used in conjunction with
-.B --comp-lzo,
+.B \-\-comp-lzo,
this option will disable OpenVPN's adaptive compression algorithm.
Normally, adaptive compression is enabled with
-.B --comp-lzo.
+.B \-\-comp-lzo.
Adaptive compression tries to optimize the case where you have
compression enabled, but you are sending predominantly uncompressible
@@ -2273,7 +2274,7 @@ the compression efficiency will be very low, triggering openvpn to disable
compression for a period of time until the next re-sample test.
.\"*********************************************************
.TP
-.B --management IP port [pw-file]
+.B \-\-management IP port [pw-file]
Enable a TCP server on
.B IP:port
to handle daemon management functions.
@@ -2292,9 +2293,9 @@ and set
.B port
to 'unix'. While the default behavior is to create a unix domain socket
that may be connected to by any process, the
-.B --management-client-user
+.B \-\-management-client-user
and
-.B --management-client-group
+.B \-\-management-client-group
directives can be used to restrict access.
The management interface provides a special mode where the TCP
@@ -2323,24 +2324,24 @@ be set to 127.0.0.1
server to local clients.
.\"*********************************************************
.TP
-.B --management-query-passwords
+.B \-\-management-query-passwords
Query management channel for private key password and
-.B --auth-user-pass
+.B \-\-auth-user-pass
username/password. Only query the management channel
for inputs which ordinarily would have been queried from the
console.
.\"*********************************************************
.TP
-.B --management-forget-disconnect
+.B \-\-management-forget-disconnect
Make OpenVPN forget passwords when management session
disconnects.
This directive does not affect the
-.B --http-proxy
+.B \-\-http-proxy
username/password. It is always cached.
.\"*********************************************************
.TP
-.B --management-hold
+.B \-\-management-hold
Start OpenVPN in a hibernating state, until a client
of the management interface explicitly starts it
with the
@@ -2348,45 +2349,45 @@ with the
command.
.\"*********************************************************
.TP
-.B --management-signal
+.B \-\-management-signal
Send SIGUSR1 signal to OpenVPN if management session disconnects.
This is useful when you wish to disconnect an OpenVPN session on
user logoff.
.\"*********************************************************
.TP
-.B --management-log-cache n
+.B \-\-management-log-cache n
Cache the most recent
.B n
lines of log file history for usage
by the management channel.
.\"*********************************************************
.TP
-.B --management-client-auth
+.B \-\-management-client-auth
Gives management interface client the responsibility
to authenticate clients after their client certificate
has been verified. See management-notes.txt in OpenVPN
distribution for detailed notes.
.\"*********************************************************
.TP
-.B --management-client-pf
+.B \-\-management-client-pf
Management interface clients must specify a packet
filter file for each connecting client. See management-notes.txt
in OpenVPN distribution for detailed notes.
.\"*********************************************************
.TP
-.B --management-client-user u
+.B \-\-management-client-user u
When the management interface is listening on a unix domain socket,
only allow connections from user
.B u.
.\"*********************************************************
.TP
-.B --management-client-group g
+.B \-\-management-client-group g
When the management interface is listening on a unix domain socket,
only allow connections from group
.B g.
.\"*********************************************************
.TP
-.B --plugin module-pathname [init-string]
+.B \-\-plugin module-pathname [init-string]
Load plug-in module from the file
.B module-pathname,
passing
@@ -2422,7 +2423,7 @@ the connection to be authenticated.
.SS Server Mode
Starting with OpenVPN 2.0, a multi-client TCP/UDP server mode
is supported, and can be enabled with the
-.B --mode server
+.B \-\-mode server
option. In server mode, OpenVPN will listen on a single
port for incoming client connections. All client
connections will be routed through a single tun or tap
@@ -2432,7 +2433,7 @@ on sufficiently fast hardware. SSL/TLS authentication must
be used in this mode.
.\"*********************************************************
.TP
-.B --server network netmask
+.B \-\-server network netmask
A helper directive designed to simplify the configuration
of OpenVPN's server mode. This directive will set up an
OpenVPN server which will allocate addresses to clients
@@ -2442,7 +2443,7 @@ for use as the server-side endpoint of the local
TUN/TAP interface.
For example,
-.B --server 10.8.0.0 255.255.255.0
+.B \-\-server 10.8.0.0 255.255.255.0
expands as follows:
.nf
@@ -2472,23 +2473,23 @@ expands as follows:
.fi
Don't use
-.B --server
+.B \-\-server
if you are ethernet bridging. Use
-.B --server-bridge
+.B \-\-server-bridge
instead.
.\"*********************************************************
.TP
-.B --server-bridge gateway netmask pool-start-IP pool-end-IP
+.B \-\-server-bridge gateway netmask pool-start-IP pool-end-IP
.TP
-.B --server-bridge ['nogw']
+.B \-\-server-bridge ['nogw']
A helper directive similar to
-.B --server
+.B \-\-server
which is designed to simplify the configuration
of OpenVPN's server mode in ethernet bridging configurations.
If
-.B --server-bridge
+.B \-\-server-bridge
is used without any parameters, it will enable a DHCP-proxy
mode, where connecting OpenVPN clients will receive an IP
address for their TAP adapter from the DHCP server running
@@ -2516,7 +2517,7 @@ IP/netmask on the bridge interface. The
and
.B netmask
parameters to
-.B --server-bridge
+.B \-\-server-bridge
can be set to either the IP/netmask of the
bridge interface, or the IP/netmask of the
default gateway/router on the bridged
@@ -2548,7 +2549,7 @@ push "route-gateway 10.8.0.4"
.fi
In another example,
-.B --server-bridge
+.B \-\-server-bridge
(without parameters) expands as follows:
.nf
@@ -2563,7 +2564,7 @@ push "route-gateway dhcp"
.fi
Or
-.B --server-bridge nogw
+.B \-\-server-bridge nogw
expands as follows:
.nf
@@ -2576,13 +2577,13 @@ tls-server
.fi
.\"*********************************************************
.TP
-.B --push "option"
+.B \-\-push "option"
Push a config file option back to the client for remote
execution. Note that
.B
option
must be enclosed in double quotes (""). The client must specify
-.B --pull
+.B \-\-pull
in its config file. The set of options which can be
pushed is limited by both feasibility and security.
Some options such as those which would execute scripts
@@ -2593,44 +2594,44 @@ cannot be pushed because the client needs to know
them before the connection to the server can be initiated.
This is a partial list of options which can currently be pushed:
-.B --route, --route-gateway, --route-delay, --redirect-gateway,
-.B --ip-win32, --dhcp-option,
-.B --inactive, --ping, --ping-exit, --ping-restart,
-.B --setenv,
-.B --persist-key, --persist-tun, --echo,
-.B --comp-lzo,
-.B --socket-flags,
-.B --sndbuf, --rcvbuf
+.B \-\-route, \-\-route-gateway, \-\-route-delay, \-\-redirect-gateway,
+.B \-\-ip-win32, \-\-dhcp-option,
+.B \-\-inactive, \-\-ping, \-\-ping-exit, \-\-ping-restart,
+.B \-\-setenv,
+.B \-\-persist-key, \-\-persist-tun, \-\-echo,
+.B \-\-comp-lzo,
+.B \-\-socket-flags,
+.B \-\-sndbuf, \-\-rcvbuf
.\"*********************************************************
.TP
-.B --push-reset
+.B \-\-push-reset
Don't inherit the global push list for a specific client instance.
Specify this option in a client-specific context such
as with a
-.B --client-config-dir
+.B \-\-client-config-dir
configuration file. This option will ignore
-.B --push
+.B \-\-push
options at the global config file level.
.\"*********************************************************
.TP
-.B --disable
+.B \-\-disable
Disable a particular client (based on the common name)
from connecting. Don't use this option to disable a client
due to key or password compromise. Use a CRL (certificate
revocation list) instead (see the
-.B --crl-verify
+.B \-\-crl-verify
option).
This option must be associated with a specific client instance,
which means that it must be specified either in a client
instance config file using
-.B --client-config-dir
+.B \-\-client-config-dir
or dynamically generated using a
-.B --client-connect
+.B \-\-client-connect
script.
.\"*********************************************************
.TP
-.B --ifconfig-pool start-IP end-IP [netmask]
+.B \-\-ifconfig-pool start-IP end-IP [netmask]
Set aside a pool of subnets to be
dynamically allocated to connecting clients, similar
to a DHCP server. For tun-style
@@ -2643,7 +2644,7 @@ parameter will also be pushed to clients.
.\"*********************************************************
.TP
-.B --ifconfig-pool-persist file [seconds]
+.B \-\-ifconfig-pool-persist file [seconds]
Persist/unpersist ifconfig-pool
data to
.B file,
@@ -2658,7 +2659,7 @@ IP address assigned to them from the ifconfig-pool.
Maintaining a long-term
association is good for clients because it allows them
to effectively use the
-.B --persist-tun
+.B \-\-persist-tun
option.
.B file
@@ -2679,32 +2680,32 @@ suggestions only, based on past associations between
a common name and IP address. They do not guarantee that the given common
name will always receive the given IP address. If you want guaranteed
assignment, use
-.B --ifconfig-push
+.B \-\-ifconfig-push
.\"*********************************************************
.TP
-.B --ifconfig-pool-linear
+.B \-\-ifconfig-pool-linear
Modifies the
-.B --ifconfig-pool
+.B \-\-ifconfig-pool
directive to
allocate individual TUN interface addresses for
clients rather than /30 subnets. NOTE: This option
is incompatible with Windows clients.
This option is deprecated, and should be replaced with
-.B --topology p2p
+.B \-\-topology p2p
which is functionally equivalent.
.\"*********************************************************
.TP
-.B --ifconfig-push local remote-netmask
+.B \-\-ifconfig-push local remote-netmask
Push virtual IP endpoints for client tunnel,
-overriding the --ifconfig-pool dynamic allocation.
+overriding the \-\-ifconfig-pool dynamic allocation.
The parameters
.B local
and
.B remote-netmask
are set according to the
-.B --ifconfig
+.B \-\-ifconfig
directive which you want to execute on the client machine to
configure the remote end of the tunnel. Note that the parameters
.B local
@@ -2717,13 +2718,13 @@ on the server at the time of client connection.
This option must be associated with a specific client instance,
which means that it must be specified either in a client
instance config file using
-.B --client-config-dir
+.B \-\-client-config-dir
or dynamically generated using a
-.B --client-connect
+.B \-\-client-connect
script.
Remember also to include a
-.B --route
+.B \-\-route
directive in the main OpenVPN config file which encloses
.B local,
so that the kernel will know to route it
@@ -2733,23 +2734,23 @@ OpenVPN's internal client IP address selection algorithm works as
follows:
.B 1
--- Use
-.B --client-connect script
+\-\- Use
+.B \-\-client-connect script
generated file for static IP (first choice).
.br
.B 2
--- Use
-.B --client-config-dir
+\-\- Use
+.B \-\-client-config-dir
file for static IP (next choice).
.br
.B 3
--- Use
-.B --ifconfig-pool
+\-\- Use
+.B \-\-ifconfig-pool
allocation for dynamic IP (last choice).
.br
.\"*********************************************************
.TP
-.B --iroute network [netmask]
+.B \-\-iroute network [netmask]
Generate an internal route to a specific
client. The
.B netmask
@@ -2760,36 +2761,36 @@ the server to a particular client, regardless
of where the client is connecting from. Remember
that you must also add the route to the system
routing table as well (such as by using the
-.B --route
+.B \-\-route
directive). The reason why two routes are needed
is that the
-.B --route
+.B \-\-route
directive routes the packet from the kernel
to OpenVPN. Once in OpenVPN, the
-.B --iroute
+.B \-\-iroute
directive routes to the specific client.
This option must be specified either in a client
instance config file using
-.B --client-config-dir
+.B \-\-client-config-dir
or dynamically generated using a
-.B --client-connect
+.B \-\-client-connect
script.
The
-.B --iroute
+.B \-\-iroute
directive also has an important interaction with
-.B --push
+.B \-\-push
"route ...".
-.B --iroute
+.B \-\-iroute
essentially defines a subnet which is owned by a
particular client (we will call this client A).
If you would like other clients to be able to reach A's
subnet, you can use
-.B --push
+.B \-\-push
"route ..."
together with
-.B --client-to-client
+.B \-\-client-to-client
to effect this. In order for all clients to see
A's subnet, OpenVPN must push this route to all clients
EXCEPT for A, since the subnet is already owned by A.
@@ -2798,11 +2799,11 @@ not pushing a route to a client
if it matches one of the client's iroutes.
.\"*********************************************************
.TP
-.B --client-to-client
+.B \-\-client-to-client
Because the OpenVPN server mode handles multiple clients
through a single tun or tap interface, it is effectively
a router. The
-.B --client-to-client
+.B \-\-client-to-client
flag tells OpenVPN to internally route client-to-client
traffic rather than pushing all client-originating traffic
to the TUN/TAP interface.
@@ -2814,20 +2815,20 @@ if you want to firewall tunnel traffic using
custom, per-client rules.
.\"*********************************************************
.TP
-.B --duplicate-cn
+.B \-\-duplicate-cn
Allow multiple clients with the same common name to concurrently connect.
In the absence of this option, OpenVPN will disconnect a client instance
upon connection of a new client having the same common name.
.\"*********************************************************
.TP
-.B --client-connect script
+.B \-\-client-connect script
Run
.B script
on client connection. The script is passed the common name
and IP address of the just-authenticated client
as environmental variables (see environmental variable section
below). The script is also passed
-the pathname of a not-yet-created temporary file as $1
+the pathname of a freshly created temporary file as $1
(i.e. the first command line argument), to be used by the script
to pass dynamically generated config file directives back to OpenVPN.
@@ -2836,7 +2837,7 @@ to be applied on the server when the client connects,
it should write it to the file named by $1.
See the
-.B --client-config-dir
+.B \-\-client-config-dir
option below for options which
can be legally used in a dynamically generated config file.
@@ -2848,18 +2849,18 @@ returns a non-zero error status, it will cause the client
to be disconnected.
.\"*********************************************************
.TP
-.B --client-disconnect
+.B \-\-client-disconnect
Like
-.B --client-connect
+.B \-\-client-connect
but called on client instance shutdown. Will not be called
unless the
-.B --client-connect
+.B \-\-client-connect
script and plugins (if defined)
were previously called on this instance with
successful (0) status returns.
The exception to this rule is if the
-.B --client-disconnect
+.B \-\-client-disconnect
script or plugins are cascaded, and at least one client-connect
function succeeded, then ALL of the client-disconnect functions for
scripts and plugins will be called on client instance object deletion,
@@ -2868,7 +2869,7 @@ an error status.
.B
.\"*********************************************************
.TP
-.B --client-config-dir dir
+.B \-\-client-config-dir dir
Specify a directory
.B dir
for custom client config files. After
@@ -2882,9 +2883,9 @@ will instead try to open and parse a default file called
This file can specify a fixed IP address for a given
client using
-.B --ifconfig-push,
+.B \-\-ifconfig-push,
as well as fixed subnets owned by the client using
-.B --iroute.
+.B \-\-iroute.
One of the useful properties of this option is that it
allows client configuration files to be conveniently
@@ -2893,28 +2894,28 @@ without needing to restart the server.
The following
options are legal in a client-specific context:
-.B --push, --push-reset, --iroute, --ifconfig-push,
+.B \-\-push, \-\-push-reset, \-\-iroute, \-\-ifconfig-push,
and
-.B --config.
+.B \-\-config.
.\"*********************************************************
.TP
-.B --ccd-exclusive
+.B \-\-ccd-exclusive
Require, as a
condition of authentication, that a connecting client has a
-.B --client-config-dir
+.B \-\-client-config-dir
file.
.\"*********************************************************
.TP
-.B --tmp-dir dir
+.B \-\-tmp-dir dir
Specify a directory
.B dir
for temporary files. This directory will be used by
-.B --client-connect
+.B \-\-client-connect
scripts to dynamically generate client-specific
configuration files.
.\"*********************************************************
.TP
-.B --hash-size r v
+.B \-\-hash-size r v
Set the size of the real address hash table to
.B r
and the virtual address table to
@@ -2922,13 +2923,13 @@ and the virtual address table to
By default, both tables are sized at 256 buckets.
.\"*********************************************************
.TP
-.B --bcast-buffers n
+.B \-\-bcast-buffers n
Allocate
.B n
buffers for broadcast datagrams (default=256).
.\"*********************************************************
.TP
-.B --tcp-queue-limit n
+.B \-\-tcp-queue-limit n
Maximum number of output packets queued before TCP (default=64).
When OpenVPN is tunneling data from a TUN/TAP device to a
@@ -2940,7 +2941,7 @@ OpenVPN will start to drop outgoing packets directed
at this client.
.\"*********************************************************
.TP
-.B --tcp-nodelay
+.B \-\-tcp-nodelay
This macro sets the TCP_NODELAY socket flag on the server
as well as pushes it to connecting clients. The TCP_NODELAY
flag disables the Nagle algorithm on TCP sockets causing
@@ -2963,13 +2964,13 @@ The macro expands as follows:
.fi
.\"*********************************************************
.TP
-.B --max-clients n
+.B \-\-max-clients n
Limit server to a maximum of
.B n
concurrent clients.
.\"*********************************************************
.TP
-.B --max-routes-per-client n
+.B \-\-max-routes-per-client n
Allow a maximum of
.B n
internal routes per client (default=256).
@@ -2979,9 +2980,9 @@ server with packets appearing to come from many unique MAC addresses,
forcing the server to deplete
virtual memory as its internal routing table expands.
This directive can be used in a
-.B --client-config-dir
+.B \-\-client-config-dir
file or auto-generated by a
-.B --client-connect
+.B \-\-client-connect
script to override the global value for a particular client.
Note that this
@@ -2989,7 +2990,7 @@ directive affects OpenVPN's internal routing table, not the
kernel routing table.
.\"*********************************************************
.TP
-.B --connect-freq n sec
+.B \-\-connect-freq n sec
Allow a maximum of
.B n
new connections per
@@ -3003,12 +3004,12 @@ DoS scenario, legitimate connections might also be refused.
For the best protection against DoS attacks in server mode,
use
-.B --proto udp
+.B \-\-proto udp
and
-.B --tls-auth.
+.B \-\-tls-auth.
.\"*********************************************************
.TP
-.B --learn-address cmd
+.B \-\-learn-address cmd
Run script or shell command
.B cmd
to validate client virtual addresses or routes.
@@ -3016,19 +3017,19 @@ to validate client virtual addresses or routes.
.B cmd
will be executed with 3 parameters:
-.B [1] operation --
+.B [1] operation \-\-
"add", "update", or "delete" based on whether or not
the address is being added to, modified, or deleted from
OpenVPN's internal routing table.
.br
-.B [2] address --
+.B [2] address \-\-
The address being learned or unlearned. This can be
an IPv4 address such as "198.162.10.14", an IPv4 subnet
such as "198.162.10.0/24", or an ethernet MAC address (when
-.B --dev tap
+.B \-\-dev tap
is being used) such as "00:FF:01:02:03:04".
.br
-.B [3] common name --
+.B [3] common name \-\-
The common name on the certificate associated with the
client linked to this address. Only present for "add"
or "update" operations, not "delete".
@@ -3048,7 +3049,7 @@ policies with regard to the client's high-level common name,
rather than the low level client virtual addresses.
.\"*********************************************************
.TP
-.B --auth-user-pass-verify script method
+.B \-\-auth-user-pass-verify script method
Require the client to provide a username/password (possibly
in addition to a client certificate) for authentication.
@@ -3079,10 +3080,10 @@ will be passed as an argument to
and the file will be automatically deleted by OpenVPN after
the script returns. The location of the temporary file is
controlled by the
-.B --tmp-dir
+.B \-\-tmp-dir
option, and will default to the current directory if unspecified.
For security, consider setting
-.B --tmp-dir
+.B \-\-tmp-dir
to a volatile storage medium such as
.B /dev/shm
(if available) to prevent the username/password file from touching the hard drive.
@@ -3114,7 +3115,7 @@ For a sample script that performs PAM authentication, see
in the OpenVPN source distribution.
.\"*********************************************************
.TP
-.B --opt-verify
+.B \-\-opt-verify
Clients that connect with options that are incompatible
with those of the server will be disconnected.
@@ -3124,16 +3125,16 @@ comp-lzo, fragment, keydir, cipher, auth, keysize, secret,
no-replay, no-iv, tls-auth, key-method, tls-server, and tls-client.
This option requires that
-.B --disable-occ
+.B \-\-disable-occ
NOT be used.
.\"*********************************************************
.TP
-.B --auth-user-pass-optional
+.B \-\-auth-user-pass-optional
Allow connections by clients that do not specify a username/password.
Normally, when
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
or
-.B --management-client-auth
+.B \-\-management-client-auth
is specified (or an authentication plugin module), the
OpenVPN server daemon will require connecting clients to specify a
username and password. This option makes the submission of a username/password
@@ -3146,35 +3147,35 @@ to empty strings (""). The authentication module/script MUST have logic
to detect this condition and respond accordingly.
.\"*********************************************************
.TP
-.B --client-cert-not-required
+.B \-\-client-cert-not-required
Don't require client certificate, client will authenticate
using username/password only. Be aware that using this directive
is less secure than requiring certificates from all clients.
If you use this directive, the
entire responsibility of authentication will rest on your
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
script, so keep in mind that bugs in your script
could potentially compromise the security of your VPN.
If you don't use this directive, but you also specify an
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
script, then OpenVPN will perform double authentication. The
client certificate verification AND the
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
script will need to succeed in order for a client to be
authenticated and accepted onto the VPN.
.\"*********************************************************
.TP
-.B --username-as-common-name
+.B \-\-username-as-common-name
For
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
authentication, use
the authenticated username as the common name,
rather than the common name from the client cert.
.\"*********************************************************
.TP
-.B --no-name-remapping
+.B \-\-no-name-remapping
Allow Common Name, X509 Subject, and username strings to include
any printable character including space, but excluding control
characters such as tab, newline, and carriage-return.
@@ -3195,7 +3196,7 @@ disable the remapping feature. Don't use this option unless you
know what you are doing!
.\"*********************************************************
.TP
-.B --port-share host port
+.B \-\-port-share host port
When run in TCP server mode, share the OpenVPN port with
another application, such as an HTTPS server. If OpenVPN
senses a connection to its port which is using a non-OpenVPN
@@ -3210,13 +3211,13 @@ Not implemented on Windows.
.SS Client Mode
Use client mode when connecting to an OpenVPN server
which has
-.B --server, --server-bridge,
+.B \-\-server, \-\-server-bridge,
or
-.B --mode server
+.B \-\-mode server
in it's configuration.
.\"*********************************************************
.TP
-.B --client
+.B \-\-client
A helper directive designed to simplify the configuration
of OpenVPN's client mode. This directive is equivalent to:
@@ -3230,33 +3231,33 @@ of OpenVPN's client mode. This directive is equivalent to:
.fi
.\"*********************************************************
.TP
-.B --pull
+.B \-\-pull
This option must be used on a client which is connecting
to a multi-client server. It indicates to OpenVPN that it
should accept options pushed by the server, provided they
are part of the legal set of pushable options (note that the
-.B --pull
+.B \-\-pull
option is implied by
-.B --client
+.B \-\-client
).
In particular,
-.B --pull
+.B \-\-pull
allows the server to push routes to the client, so you should
not use
-.B --pull
+.B \-\-pull
or
-.B --client
+.B \-\-client
in situations where you don't trust the server to have control
over the client's routing table.
.\"*********************************************************
.TP
-.B --auth-user-pass [up]
+.B \-\-auth-user-pass [up]
Authenticate with server using username/password.
.B up
is a file containing username/password on 2 lines (Note: OpenVPN
will only read passwords from a file if it has been built
-with the --enable-password-save configure option, or on Windows
+with the \-\-enable-password-save configure option, or on Windows
by defining ENABLE_PASSWORD_SAVE in config-win32.h).
If
@@ -3265,12 +3266,12 @@ is omitted, username/password will be prompted from the
console.
The server configuration must specify an
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
script to verify the username/password provided by
the client.
.\"*********************************************************
.TP
-.B --auth-retry type
+.B \-\-auth-retry type
Controls how OpenVPN responds to username/password verification
errors such as the client-side response to an AUTH_FAILED message from the server
or verification failure of the private key password.
@@ -3281,40 +3282,40 @@ of error.
An AUTH_FAILED message is generated by the server if the client
fails
-.B --auth-user-pass
+.B \-\-auth-user-pass
authentication, or if the server-side
-.B --client-connect
+.B \-\-client-connect
script returns an error status when the client
tries to connect.
.B type
can be one of:
-.B none --
+.B none \-\-
Client will exit with a fatal error (this is the default).
.br
-.B nointeract --
+.B nointeract \-\-
Client will retry the connection without requerying for an
-.B --auth-user-pass
+.B \-\-auth-user-pass
username/password. Use this option for unattended clients.
.br
-.B interact --
+.B interact \-\-
Client will requery for an
-.B --auth-user-pass
+.B \-\-auth-user-pass
username/password and/or private key password before attempting a reconnection.
Note that while this option cannot be pushed, it can be controlled
from the management interface.
.\"*********************************************************
.TP
-.B --server-poll-timeout n
+.B \-\-server-poll-timeout n
when polling possible remote servers to connect to
in a round-robin fashion, spend no more than
.B n
seconds waiting for a response before trying the next server.
.\"*********************************************************
.TP
-.B --explicit-exit-notify [n]
+.B \-\-explicit-exit-notify [n]
In UDP client mode or point-to-point mode, send server/peer an exit notification
if tunnel is restarted or OpenVPN process is exited. In client mode, on
exit/restart, this
@@ -3329,12 +3330,12 @@ These options are meaningful for both Static & TLS-negotiated key modes
(must be compatible between peers).
.\"*********************************************************
.TP
-.B --secret file [direction]
+.B \-\-secret file [direction]
Enable Static Key encryption mode (non-TLS).
Use pre-shared secret
.B file
which was generated with
-.B --genkey.
+.B \-\-genkey.
The optional
.B direction
@@ -3365,7 +3366,7 @@ supports the
.B direction
parameter, will also support 2048 bit key file generation
using the
-.B --genkey
+.B \-\-genkey
option.
Static key encryption mode has certain advantages,
@@ -3395,7 +3396,7 @@ would see nothing
but random-looking data.
.\"*********************************************************
.TP
-.B --auth alg
+.B \-\-auth alg
Authenticate packets with HMAC using message
digest algorithm
.B alg.
@@ -3410,7 +3411,7 @@ OpenVPN's usage of HMAC is to first encrypt a packet, then HMAC the resulting ci
In static-key encryption mode, the HMAC key
is included in the key file generated by
-.B --genkey.
+.B \-\-genkey.
In TLS mode, the HMAC key is dynamically generated and shared
between peers via the TLS control channel. If OpenVPN receives a packet with
a bad HMAC it will drop the packet.
@@ -3423,7 +3424,7 @@ For more information on HMAC see
.I http://www.cs.ucsd.edu/users/mihir/papers/hmac.html
.\"*********************************************************
.TP
-.B --cipher alg
+.B \-\-cipher alg
Encrypt packets with cipher algorithm
.B alg.
The default is
@@ -3438,7 +3439,7 @@ For more information on blowfish, see
To see other ciphers that are available with
OpenVPN, use the
-.B --show-ciphers
+.B \-\-show-ciphers
option.
OpenVPN supports the CBC, CFB, and OFB cipher modes,
@@ -3450,10 +3451,10 @@ Set
to disable encryption.
.\"*********************************************************
.TP
-.B --keysize n
+.B \-\-keysize n
Size of cipher key in bits (optional).
If unspecified, defaults to cipher-specific default. The
-.B --show-ciphers
+.B \-\-show-ciphers
option (see below) shows all available OpenSSL ciphers,
their default key sizes, and whether the key size can
be changed. Use care in changing a cipher's default
@@ -3463,7 +3464,7 @@ larger key may offer no real guarantee of greater
security, or may even reduce security.
.\"*********************************************************
.TP
-.B --prng alg [nsl]
+.B \-\-prng alg [nsl]
(Advanced) For PRNG (Pseudo-random number generator),
use digest algorithm
.B alg
@@ -3478,19 +3479,19 @@ to disable the PRNG and use the OpenSSL RAND_bytes function
instead for all of OpenVPN's pseudo-random number needs.
.\"*********************************************************
.TP
-.B --engine [engine-name]
+.B \-\-engine [engine-name]
Enable OpenSSL hardware-based crypto engine functionality.
If
.B engine-name
is specified,
use a specific crypto engine. Use the
-.B --show-engines
+.B \-\-show-engines
standalone option to list the crypto engines which are
supported by OpenSSL.
.\"*********************************************************
.TP
-.B --no-replay
+.B \-\-no-replay
(Advanced) Disable OpenVPN's protection against replay attacks.
Don't use this option unless you are prepared to make
a tradeoff of greater efficiency in exchange for less
@@ -3534,7 +3535,7 @@ algorithm used
by IPSec.
.\"*********************************************************
.TP
-.B --replay-window n [t]
+.B \-\-replay-window n [t]
Use a replay protection sliding-window of size
.B n
and a time window of
@@ -3549,9 +3550,9 @@ is 15 seconds.
This option is only relevant in UDP mode, i.e.
when either
-.B --proto udp
+.B \-\-proto udp
is specifed, or no
-.B --proto
+.B \-\-proto
option is specified.
When OpenVPN tunnels IP packets over UDP, there is the possibility that
@@ -3563,7 +3564,7 @@ the TCP/IP protocol stack, provided they satisfy several constraints.
.B (a)
The packet cannot be a replay (unless
-.B --no-replay
+.B \-\-no-replay
is specified, which disables replay protection altogether).
.B (b)
@@ -3585,7 +3586,7 @@ a larger value for
Satellite links in particular often require this.
If you run OpenVPN at
-.B --verb 4,
+.B \-\-verb 4,
you will see the message "Replay-window backtrack occurred [x]"
every time the maximum sequence number backtrack seen thus far
increases. This can be used to calibrate
@@ -3621,7 +3622,7 @@ parameters of what is to be expected from the physical IP layer. The problem
is easily fixed by simply using TCP as the VPN transport layer.
.\"*********************************************************
.TP
-.B --mute-replay-warnings
+.B \-\-mute-replay-warnings
Silence the output of replay warnings, which are a common
false alarm on WiFi networks. This option preserves
the security of the replay protection code without
@@ -3629,7 +3630,7 @@ the verbosity associated with warnings about duplicate
packets.
.\"*********************************************************
.TP
-.B --replay-persist file
+.B \-\-replay-persist file
Persist replay-protection state across sessions using
.B file
to save and reload the state.
@@ -3637,7 +3638,7 @@ to save and reload the state.
This option will strengthen protection against replay attacks,
especially when you are using OpenVPN in a dynamic context (such
as with
-.B --inetd)
+.B \-\-inetd)
when OpenVPN sessions are frequently started and stopped.
This option will keep a disk copy of the current replay protection
@@ -3648,12 +3649,12 @@ which were already received by the prior session.
This option only makes sense when replay protection is enabled
(the default) and you are using either
-.B --secret
+.B \-\-secret
(shared-secret key mode) or TLS mode with
-.B --tls-auth.
+.B \-\-tls-auth.
.\"*********************************************************
.TP
-.B --no-iv
+.B \-\-no-iv
(Advanced) Disable OpenVPN's use of IV (cipher initialization vector).
Don't use this option unless you are prepared to make
a tradeoff of greater efficiency in exchange for less
@@ -3674,24 +3675,24 @@ space-saving optimization that uses the unique identifier for
datagram replay protection as the IV.
.\"*********************************************************
.TP
-.B --test-crypto
+.B \-\-test-crypto
Do a self-test of OpenVPN's crypto options by encrypting and
decrypting test packets using the data channel encryption options
specified above. This option does not require a peer to function,
and therefore can be specified without
-.B --dev
+.B \-\-dev
or
-.B --remote.
+.B \-\-remote.
The typical usage of
-.B --test-crypto
+.B \-\-test-crypto
would be something like this:
-.B openvpn --test-crypto --secret key
+.B openvpn \-\-test-crypto \-\-secret key
or
-.B openvpn --test-crypto --secret key --verb 9
+.B openvpn \-\-test-crypto \-\-secret key \-\-verb 9
This option is very useful to test OpenVPN after it has been ported to
a new platform, or to isolate problems in the compiler, OpenSSL
@@ -3715,17 +3716,17 @@ including certificate-based authentication and Diffie Hellman forward secrecy.
To use TLS mode, each peer that runs OpenVPN should have its own local
certificate/key pair (
-.B --cert
+.B \-\-cert
and
-.B --key
+.B \-\-key
), signed by the root certificate which is specified
in
-.B --ca.
+.B \-\-ca.
When two OpenVPN peers connect, each presents its local certificate to the
other. Each peer will then check that its partner peer presented a
certificate which was signed by the master root certificate as specified in
-.B --ca.
+.B \-\-ca.
If that check on both peers succeeds, then the TLS negotiation
will succeed, both OpenVPN
@@ -3742,18 +3743,18 @@ The easy-rsa package is also rendered in web form here:
.I http://openvpn.net/easyrsa.html
.\"*********************************************************
.TP
-.B --tls-server
+.B \-\-tls-server
Enable TLS and assume server role during TLS handshake. Note that
OpenVPN is designed as a peer-to-peer application. The designation
of client or server is only for the purpose of negotiating the TLS
control channel.
.\"*********************************************************
.TP
-.B --tls-client
+.B \-\-tls-client
Enable TLS and assume client role during TLS handshake.
.\"*********************************************************
.TP
-.B --ca file
+.B \-\-ca file
Certificate authority (CA) file in .pem format, also referred to as the
.I root
certificate. This file can have multiple
@@ -3775,10 +3776,10 @@ production environment, since by virtue of the fact that
they are distributed with OpenVPN, they are totally insecure.
.\"*********************************************************
.TP
-.B --dh file
+.B \-\-dh file
File containing Diffie Hellman parameters
in .pem format (required for
-.B --tls-server
+.B \-\-tls-server
only). Use
.B openssl dhparam -out dh1024.pem 1024
@@ -3788,15 +3789,15 @@ included with the OpenVPN distribution. Diffie Hellman parameters
may be considered public.
.\"*********************************************************
.TP
-.B --cert file
-Local peer's signed certificate in .pem format -- must be signed
+.B \-\-cert file
+Local peer's signed certificate in .pem format \-\- must be signed
by a certificate authority whose certificate is in
-.B --ca file.
+.B \-\-ca file.
Each peer in an OpenVPN link running in TLS mode should have its own
certificate and private key file. In addition, each certificate should
have been signed by the key of a certificate
authority whose public key resides in the
-.B --ca
+.B \-\-ca
certificate authority file.
You can easily make your own certificate authority (see above) or pay money
to use a commercial service such as thawte.com (in which case you will be
@@ -3821,7 +3822,7 @@ Note that the
command reads the location of the certificate authority key from its
configuration file such as
.B /usr/share/ssl/openssl.cnf
--- note also
+\-\- note also
that for certificate authority functions, you must set up the files
.B index.txt
(may be empty) and
@@ -3832,90 +3833,90 @@ that for certificate authority functions, you must set up the files
).
.\"*********************************************************
.TP
-.B --key file
+.B \-\-key file
Local peer's private key in .pem format. Use the private key which was generated
when you built your peer's certificate (see
.B -cert file
above).
.\"*********************************************************
.TP
-.B --pkcs12 file
+.B \-\-pkcs12 file
Specify a PKCS #12 file containing local private key,
local certificate, and root CA certificate.
This option can be used instead of
-.B --ca, --cert,
+.B \-\-ca, \-\-cert,
and
-.B --key.
+.B \-\-key.
.\"*********************************************************
.TP
-.B --pkcs11-cert-private [0|1]...
+.B \-\-pkcs11-cert-private [0|1]...
Set if access to certificate object should be performed after login.
Every provider has its own setting.
.\"*********************************************************
.TP
-.B --pkcs11-id name
+.B \-\-pkcs11-id name
Specify the serialized certificate id to be used. The id can be gotten
by the standalone
-.B --show-pkcs11-ids
+.B \-\-show-pkcs11-ids
option.
.\"*********************************************************
.TP
-.B --pkcs11-id-management
+.B \-\-pkcs11-id-management
Acquire PKCS#11 id from management interface. In this case a NEED-STR 'pkcs11-id-request'
real-time message will be triggered, application may use pkcs11-id-count command to
retrieve available number of certificates, and pkcs11-id-get command to retrieve certificate
id and certificate body.
.\"*********************************************************
.TP
-.B --pkcs11-pin-cache seconds
+.B \-\-pkcs11-pin-cache seconds
Specify how many seconds the PIN can be cached, the default is until the token is removed.
.\"*********************************************************
.TP
-.B --pkcs11-protected-authentication [0|1]...
+.B \-\-pkcs11-protected-authentication [0|1]...
Use PKCS#11 protected authentication path, useful for biometric and external
keypad devices.
Every provider has its own setting.
.\"*********************************************************
.TP
-.B --pkcs11-providers provider...
+.B \-\-pkcs11-providers provider...
Specify a RSA Security Inc. PKCS #11 Cryptographic Token Interface (Cryptoki) providers
to load.
This option can be used instead of
-.B --cert, --key,
+.B \-\-cert, \-\-key,
and
-.B --pkcs12.
+.B \-\-pkcs12.
.\"*********************************************************
.TP
-.B --pkcs11-private-mode mode...
+.B \-\-pkcs11-private-mode mode...
Specify which method to use in order to perform private key operations.
A different mode can be specified for each provider.
Mode is encoded as hex number, and can be a mask one of the following:
.B 0
-(default) -- Try to determind automatically.
+(default) \-\- Try to determind automatically.
.br
.B 1
--- Use sign.
+\-\- Use sign.
.br
.B 2
--- Use sign recover.
+\-\- Use sign recover.
.br
.B 4
--- Use decrypt.
+\-\- Use decrypt.
.br
.B 8
--- Use unwrap.
+\-\- Use unwrap.
.br
.\"*********************************************************
.TP
-.B --cryptoapicert select-string
+.B \-\-cryptoapicert select-string
Load the certificate and private key from the
Windows Certificate System Store (Windows Only).
Use this option instead of
-.B --cert
+.B \-\-cert
and
-.B --key.
+.B \-\-key.
This makes
it possible to use any smart card, supported by Windows, but also any
@@ -3941,7 +3942,7 @@ Certificate Store GUI.
.\"*********************************************************
.TP
-.B --key-method m
+.B \-\-key-method m
Use data channel key negotiation method
.B m.
The key method must match on both sides of the connection.
@@ -3969,16 +3970,16 @@ of keying occur:
of the connection producing certificates and verifying the certificate
(or other authentication info provided) of
the other side. The
-.B --key-method
+.B \-\-key-method
parameter has no effect on this process.
(2) After the TLS connection is established, the tunnel session keys are
separately negotiated over the existing secure TLS channel. Here,
-.B --key-method
+.B \-\-key-method
determines the derivation of the tunnel session keys.
.\"*********************************************************
.TP
-.B --tls-cipher l
+.B \-\-tls-cipher l
A list
.B l
of allowable TLS ciphers delimited by a colon (":").
@@ -3988,11 +3989,11 @@ version rollback attack where a man-in-the-middle attacker tries
to force two peers to negotiate to the lowest level
of security they both support.
Use
-.B --show-tls
+.B \-\-show-tls
to see a list of supported TLS ciphers.
.\"*********************************************************
.TP
-.B --tls-timeout n
+.B \-\-tls-timeout n
Packet retransmit timeout on TLS control channel
if no acknowledgment from remote within
.B n
@@ -4009,7 +4010,7 @@ the higher level network protocols running on top of the tunnel
such as TCP expect this role to be left to them.
.\"*********************************************************
.TP
-.B --reneg-bytes n
+.B \-\-reneg-bytes n
Renegotiate data channel key after
.B n
bytes sent or received (disabled by default).
@@ -4019,13 +4020,13 @@ a number of seconds. A key renegotiation will be forced
if any of these three criteria are met by either peer.
.\"*********************************************************
.TP
-.B --reneg-pkts n
+.B \-\-reneg-pkts n
Renegotiate data channel key after
.B n
packets sent and received (disabled by default).
.\"*********************************************************
.TP
-.B --reneg-sec n
+.B \-\-reneg-sec n
Renegotiate data channel key after
.B n
seconds (default=3600).
@@ -4036,16 +4037,16 @@ cause the end user to be challenged to reauthorize once per hour.
Also, keep in mind that this option can be used on both the client and server,
and whichever uses the lower value will be the one to trigger the renegotiation.
A common mistake is to set
-.B --reneg-sec
+.B \-\-reneg-sec
to a higher value on either the client or server, while the other side of the connection
is still using the default value of 3600 seconds, meaning that the renegotiation will
-still occur once per 3600 seconds. The solution is to increase --reneg-sec on both the
+still occur once per 3600 seconds. The solution is to increase \-\-reneg-sec on both the
client and server, or set it to 0 on one side of the connection (to disable), and to
your chosen value on the other side.
.\"*********************************************************
.TP
-.B --hand-window n
-Handshake Window -- the TLS-based key exchange must finalize within
+.B \-\-hand-window n
+Handshake Window \-\- the TLS-based key exchange must finalize within
.B n
seconds
of handshake initiation by any peer (default = 60 seconds).
@@ -4053,47 +4054,47 @@ If the handshake fails
we will attempt to reset our connection with our peer and try again.
Even in the event of handshake failure we will still use
our expiring key for up to
-.B --tran-window
+.B \-\-tran-window
seconds to maintain continuity of transmission of tunnel
data.
.\"*********************************************************
.TP
-.B --tran-window n
-Transition window -- our old key can live this many seconds
+.B \-\-tran-window n
+Transition window \-\- our old key can live this many seconds
after a new a key renegotiation begins (default = 3600 seconds).
This feature allows for a graceful transition from old to new
key, and removes the key renegotiation sequence from the critical
path of tunnel data forwarding.
.\"*********************************************************
.TP
-.B --single-session
+.B \-\-single-session
After initially connecting to a remote peer, disallow any new connections.
Using this
option means that a remote peer cannot connect, disconnect, and then
reconnect.
If the daemon is reset by a signal or
-.B --ping-restart,
+.B \-\-ping-restart,
it will allow one new connection.
-.B --single-session
+.B \-\-single-session
can be used with
-.B --ping-exit
+.B \-\-ping-exit
or
-.B --inactive
+.B \-\-inactive
to create a single dynamic session that will exit when finished.
.\"*********************************************************
.TP
-.B --tls-exit
+.B \-\-tls-exit
Exit on TLS negotiation failure.
.\"*********************************************************
.TP
-.B --tls-auth file [direction]
+.B \-\-tls-auth file [direction]
Add an additional layer of HMAC authentication on top of the TLS
control channel to protect against DoS attacks.
In a nutshell,
-.B --tls-auth
+.B \-\-tls-auth
enables a kind of "HMAC firewall" on OpenVPN's TCP/UDP port,
where TLS control channel packets
bearing an incorrect HMAC signature can be dropped immediately without
@@ -4104,7 +4105,7 @@ response.
.B (1)
An OpenVPN static key file generated by
-.B --genkey
+.B \-\-genkey
(required if
.B direction
parameter is used).
@@ -4122,19 +4123,19 @@ OpenVPN will first try format (1), and if the file fails to parse as
a static key file, format (2) will be used.
See the
-.B --secret
+.B \-\-secret
option for more information on the optional
.B direction
parameter.
-.B --tls-auth
+.B \-\-tls-auth
is recommended when you are running OpenVPN in a mode where
it is listening for packets from any IP address, such as when
-.B --remote
+.B \-\-remote
is not specified, or
-.B --remote
+.B \-\-remote
is specified with
-.B --float.
+.B \-\-float.
The rationale for
this feature is as follows. TLS requires a multi-packet exchange
@@ -4161,7 +4162,7 @@ An important rule of thumb in reducing vulnerability to DoS attacks is to
minimize the amount of resources a potential, but as yet unauthenticated,
client is able to consume.
-.B --tls-auth
+.B \-\-tls-auth
does this by signing every TLS control channel packet with an HMAC signature,
including packets which are sent before the TLS level has had a chance
to authenticate the peer.
@@ -4169,20 +4170,20 @@ The result is that packets without
the correct signature can be dropped immediately upon reception,
before they have a chance to consume additional system resources
such as by initiating a TLS handshake.
-.B --tls-auth
+.B \-\-tls-auth
can be strengthened by adding the
-.B --replay-persist
+.B \-\-replay-persist
option which will keep OpenVPN's replay protection state
in a file so that it is not lost across restarts.
It should be emphasized that this feature is optional and that the
passphrase/key file used with
-.B --tls-auth
+.B \-\-tls-auth
gives a peer nothing more than the power to initiate a TLS
handshake. It is not used to encrypt or authenticate any tunnel data.
.\"*********************************************************
.TP
-.B --askpass [file]
+.B \-\-askpass [file]
Get certificate password from console or
.B file
before we daemonize.
@@ -4191,7 +4192,7 @@ For the extremely
security conscious, it is possible to protect your private key with
a password. Of course this means that every time the OpenVPN
daemon is started you must be there to type the password. The
-.B --askpass
+.B \-\-askpass
option allows you to start OpenVPN from the command line. It will
query you for a password before it daemonizes. To protect a private
key with a password you should omit the
@@ -4208,15 +4209,15 @@ Keep in mind that storing your password in a file
to a certain extent invalidates the extra security provided by
using an encrypted key (Note: OpenVPN
will only read passwords from a file if it has been built
-with the --enable-password-save configure option, or on Windows
+with the \-\-enable-password-save configure option, or on Windows
by defining ENABLE_PASSWORD_SAVE in config-win32.h).
.\"*********************************************************
.TP
-.B --auth-nocache
+.B \-\-auth-nocache
Don't cache
-.B --askpass
+.B \-\-askpass
or
-.B --auth-user-pass
+.B \-\-auth-user-pass
username/passwords in virtual memory.
If specified, this directive will cause OpenVPN to immediately
@@ -4226,19 +4227,19 @@ from stdin, which may be multiple times during the duration of an
OpenVPN session.
This directive does not affect the
-.B --http-proxy
+.B \-\-http-proxy
username/password. It is always cached.
.\"*********************************************************
.TP
-.B --tls-verify cmd
+.B \-\-tls-verify cmd
Execute shell command
.B cmd
to verify the X509 name of a
pending TLS connection that has otherwise passed all other
tests of certification (except for revocation via
-.B --crl-verify
+.B \-\-crl-verify
directive; the revocation test occurs after the
-.B --tls-verify
+.B \-\-tls-verify
test).
.B cmd
@@ -4271,7 +4272,7 @@ to
to build a command line which will be passed to the script.
.\"*********************************************************
.TP
-.B --tls-remote name
+.B \-\-tls-remote name
Accept connections only from a host with X509 name
or common name equal to
.B name.
@@ -4281,24 +4282,24 @@ of verification.
Name can also be a common name prefix, for example if you
want a client to only accept connections to "Server-1",
"Server-2", etc., you can simply use
-.B --tls-remote Server
+.B \-\-tls-remote Server
Using a common name prefix is a useful alternative to managing
a CRL (Certificate Revocation List) on the client, since it allows the client
to refuse all certificates except for those associated
with designated servers.
-.B --tls-remote
+.B \-\-tls-remote
is a useful replacement for the
-.B --tls-verify
+.B \-\-tls-verify
option to verify the remote host, because
-.B --tls-remote
+.B \-\-tls-remote
works in a
-.B --chroot
+.B \-\-chroot
environment too.
.\"*********************************************************
.TP
-.B --ns-cert-type client|server
+.B \-\-ns-cert-type client|server
Require that peer certificate was signed with an explicit
.B nsCertType
designation of "client" or "server".
@@ -4313,19 +4314,19 @@ field set to "server".
If the server certificate's nsCertType field is set
to "server", then the clients can verify this with
-.B --ns-cert-type server.
+.B \-\-ns-cert-type server.
This is an important security precaution to protect against
a man-in-the-middle attack where an authorized client
attempts to connect to another client by impersonating the server.
The attack is easily prevented by having clients verify
the server certificate using any one of
-.B --ns-cert-type, --tls-remote,
+.B \-\-ns-cert-type, \-\-tls-remote,
or
-.B --tls-verify.
+.B \-\-tls-verify.
.\"*********************************************************
.TP
-.B --remote-cert-ku v...
+.B \-\-remote-cert-ku v...
Require that peer certificate was signed with an explicit
.B key usage.
@@ -4336,7 +4337,7 @@ The key usage should be encoded in hex, more than one key
usage can be specified.
.\"*********************************************************
.TP
-.B --remote-cert-eku oid
+.B \-\-remote-cert-eku oid
Require that peer certificate was signed with an explicit
.B extended key usage.
@@ -4347,7 +4348,7 @@ The extended key usage should be encoded in oid notation, or
OpenSSL symbolic representation.
.\"*********************************************************
.TP
-.B --remote-cert-tls client|server
+.B \-\-remote-cert-tls client|server
Require that peer certificate was signed with an explicit
.B key usage
and
@@ -4358,18 +4359,18 @@ This is a useful security option for clients, to ensure that
the host they connect to is a designated server.
The
-.B --remote-cert-tls client
+.B \-\-remote-cert-tls client
option is equivalent to
.B
---remote-cert-ku 80 08 88 --remote-cert-eku "TLS Web Client Authentication"
+\-\-remote-cert-ku 80 08 88 \-\-remote-cert-eku "TLS Web Client Authentication"
The key usage is digitalSignature and/or keyAgreement.
The
-.B --remote-cert-tls server
+.B \-\-remote-cert-tls server
option is equivalent to
.B
---remote-cert-ku a0 88 --remote-cert-eku "TLS Web Server Authentication"
+\-\-remote-cert-ku a0 88 \-\-remote-cert-eku "TLS Web Server Authentication"
The key usage is digitalSignature and ( keyEncipherment or keyAgreement ).
@@ -4378,12 +4379,12 @@ a man-in-the-middle attack where an authorized client
attempts to connect to another client by impersonating the server.
The attack is easily prevented by having clients verify
the server certificate using any one of
-.B --remote-cert-tls, --tls-remote,
+.B \-\-remote-cert-tls, \-\-tls-remote,
or
-.B --tls-verify.
+.B \-\-tls-verify.
.\"*********************************************************
.TP
-.B --crl-verify crl
+.B \-\-crl-verify crl
Check peer certificate against the file
.B crl
in PEM format.
@@ -4403,28 +4404,28 @@ if the root certificate key itself was compromised.
.SS SSL Library information:
.\"*********************************************************
.TP
-.B --show-ciphers
+.B \-\-show-ciphers
(Standalone)
Show all cipher algorithms to use with the
-.B --cipher
+.B \-\-cipher
option.
.\"*********************************************************
.TP
-.B --show-digests
+.B \-\-show-digests
(Standalone)
Show all message digest algorithms to use with the
-.B --auth
+.B \-\-auth
option.
.\"*********************************************************
.TP
-.B --show-tls
+.B \-\-show-tls
(Standalone)
Show all TLS ciphers (TLS used only as a control channel). The TLS
ciphers will be sorted from highest preference (most secure) to
lowest.
.\"*********************************************************
.TP
-.B --show-engines
+.B \-\-show-engines
(Standalone)
Show currently available hardware-based crypto acceleration
engines supported by the OpenSSL library.
@@ -4433,18 +4434,18 @@ engines supported by the OpenSSL library.
Used only for non-TLS static key encryption mode.
.\"*********************************************************
.TP
-.B --genkey
+.B \-\-genkey
(Standalone)
Generate a random key to be used as a shared secret,
for use with the
-.B --secret
+.B \-\-secret
option. This file must be shared with the
peer over a pre-existing secure channel such as
.BR scp (1)
.
.\"*********************************************************
.TP
-.B --secret file
+.B \-\-secret file
Write key to
.B file.
.\"*********************************************************
@@ -4453,7 +4454,7 @@ Available with linux 2.4.7+. These options comprise a standalone mode
of OpenVPN which can be used to create and delete persistent tunnels.
.\"*********************************************************
.TP
-.B --mktun
+.B \-\-mktun
(Standalone)
Create a persistent tunnel on platforms which support them such
as Linux. Normally TUN/TAP tunnels exist only for
@@ -4464,9 +4465,9 @@ only when they are deleted or the machine is rebooted.
One of the advantages of persistent tunnels is that they eliminate the
need for separate
-.B --up
+.B \-\-up
and
-.B --down
+.B \-\-down
scripts to run the appropriate
.BR ifconfig (8)
and
@@ -4478,40 +4479,40 @@ Another advantage is that open connections through the TUN/TAP-based tunnel
will not be reset if the OpenVPN peer restarts. This can be useful to
provide uninterrupted connectivity through the tunnel in the event of a DHCP
reset of the peer's public IP address (see the
-.B --ipchange
+.B \-\-ipchange
option above).
One disadvantage of persistent tunnels is that it is harder to automatically
configure their MTU value (see
-.B --link-mtu
+.B \-\-link-mtu
and
-.B --tun-mtu
+.B \-\-tun-mtu
above).
On some platforms such as Windows, TAP-Win32 tunnels are persistent by
default.
.\"*********************************************************
.TP
-.B --rmtun
+.B \-\-rmtun
(Standalone)
Remove a persistent tunnel.
.\"*********************************************************
.TP
-.B --dev tunX | tapX
+.B \-\-dev tunX | tapX
TUN/TAP device
.\"*********************************************************
.TP
-.B --user user
+.B \-\-user user
Optional user to be owner of this tunnel.
.\"*********************************************************
.TP
-.B --group group
+.B \-\-group group
Optional group to be owner of this tunnel.
.\"*********************************************************
.SS Windows-Specific Options:
.\"*********************************************************
.TP
-.B --win-sys path|'env'
+.B \-\-win-sys path|'env'
Set the Windows system directory pathname to use when looking for system
executables such as
.B route.exe
@@ -4527,23 +4528,23 @@ indicates that the pathname should be read from the
environmental variable.
.\"*********************************************************
.TP
-.B --ip-win32 method
+.B \-\-ip-win32 method
When using
-.B --ifconfig
+.B \-\-ifconfig
on Windows, set the TAP-Win32 adapter
IP address and netmask using
.B method.
Don't use this option unless you are also using
-.B --ifconfig.
+.B \-\-ifconfig.
-.B manual --
+.B manual \-\-
Don't set the IP address or netmask automatically.
Instead output a message
to the console telling the user to configure the
adapter manually and indicating the IP/netmask which
OpenVPN expects the adapter to be set to.
-.B dynamic [offset] [lease-time] --
+.B dynamic [offset] [lease-time] \-\-
Automatically set the IP address and netmask by replying to
DHCP query messages generated by the kernel. This mode is
probably the "cleanest" solution
@@ -4553,13 +4554,13 @@ this mode: (1) The TCP/IP properties for the TAP-Win32
adapter must be set to "Obtain an IP address automatically," and
(2) OpenVPN needs to claim an IP address in the subnet for use
as the virtual DHCP server address. By default in
-.B --dev tap
+.B \-\-dev tap
mode, OpenVPN will
take the normally unused first address in the subnet. For example,
if your subnet is 192.168.4.0 netmask 255.255.255.0, then
OpenVPN will take the IP address 192.168.4.0 to use as the
virtual DHCP server address. In
-.B --dev tun
+.B \-\-dev tun
mode, OpenVPN will cause the DHCP server to masquerade as if it were
coming from the remote endpoint. The optional offset parameter is
an integer which is > -256 and < 256 and which defaults to 0.
@@ -4581,13 +4582,13 @@ because it prevents routes involving the TAP-Win32 adapter from
being lost when the system goes to sleep. The default
lease time is one year.
-.B netsh --
+.B netsh \-\-
Automatically set the IP address and netmask using
the Windows command-line "netsh"
command. This method appears to work correctly on
Windows XP but not Windows 2000.
-.B ipapi --
+.B ipapi \-\-
Automatically set the IP address and netmask using the
Windows IP Helper API. This approach
does not have ideal semantics, though testing has indicated
@@ -4596,7 +4597,7 @@ it is best to leave the TCP/IP properties for the TAP-Win32
adapter in their default state, i.e. "Obtain an IP address
automatically."
-.B adaptive --
+.B adaptive \-\-
(Default) Try
.B dynamic
method initially and fail over to
@@ -4626,55 +4627,55 @@ mode to restore the TAP-Win32 adapter TCP/IP properties
to a DHCP configuration.
.\"*********************************************************
.TP
-.B --route-method m
+.B \-\-route-method m
Which method
.B m
to use for adding routes on Windows?
.B adaptive
-(default) -- Try IP helper API first. If that fails, fall
+(default) \-\- Try IP helper API first. If that fails, fall
back to the route.exe shell command.
.br
.B ipapi
--- Use IP helper API.
+\-\- Use IP helper API.
.br
.B exe
--- Call the route.exe shell command.
+\-\- Call the route.exe shell command.
.\"*********************************************************
.TP
-.B --dhcp-option type [parm]
+.B \-\-dhcp-option type [parm]
Set extended TAP-Win32 TCP/IP properties, must
be used with
-.B --ip-win32 dynamic
+.B \-\-ip-win32 dynamic
or
-.B --ip-win32 adaptive.
+.B \-\-ip-win32 adaptive.
This option can be used to set additional TCP/IP properties
on the TAP-Win32 adapter, and is particularly useful for
configuring an OpenVPN client to access a Samba server
across the VPN.
-.B DOMAIN name --
+.B DOMAIN name \-\-
Set Connection-specific DNS Suffix.
-.B DNS addr --
+.B DNS addr \-\-
Set primary domain name server address. Repeat
this option to set secondary DNS server addresses.
-.B WINS addr --
+.B WINS addr \-\-
Set primary WINS server address (NetBIOS over TCP/IP Name Server).
Repeat this option to set secondary WINS server addresses.
-.B NBDD addr --
+.B NBDD addr \-\-
Set primary NBDD server address (NetBIOS over TCP/IP Datagram Distribution Server)
Repeat this option
to set secondary NBDD server addresses.
-.B NTP addr --
+.B NTP addr \-\-
Set primary NTP server address (Network Time Protocol).
Repeat this option
to set secondary NTP server addresses.
-.B NBT type --
+.B NBT type \-\-
Set NetBIOS over TCP/IP Node type. Possible options:
.B 1
= b-node (broadcasts),
@@ -4687,7 +4688,7 @@ then query name server), and
.B 8
= h-node (query name server, then broadcast).
-.B NBS scope-id --
+.B NBS scope-id \-\-
Set NetBIOS over TCP/IP Scope. A NetBIOS Scope ID provides an extended
naming service for the NetBIOS over TCP/IP (Known as NBT) module. The
primary purpose of a NetBIOS scope ID is to isolate NetBIOS traffic on
@@ -4699,19 +4700,19 @@ computers to use the same computer name, as they have different
scope IDs. The Scope ID becomes a part of the NetBIOS name, making the name unique.
(This description of NetBIOS scopes courtesy of NeonSurge@abyss.com)
-.B DISABLE-NBT --
+.B DISABLE-NBT \-\-
Disable Netbios-over-TCP/IP.
Note that if
-.B --dhcp-option
+.B \-\-dhcp-option
is pushed via
-.B --push
+.B \-\-push
to a non-windows client, the option will be saved in the client's
environment before the up script is called, under
the name "foreign_option_{n}".
.\"*********************************************************
.TP
-.B --tap-sleep n
+.B \-\-tap-sleep n
Cause OpenVPN to sleep for
.B n
seconds immediately after the TAP-Win32 adapter state
@@ -4719,21 +4720,21 @@ is set to "connected".
This option is intended to be used to troubleshoot problems
with the
-.B --ifconfig
+.B \-\-ifconfig
and
-.B --ip-win32
+.B \-\-ip-win32
options, and is used to give
the TAP-Win32 adapter time to come up before
Windows IP Helper API operations are applied to it.
.\"*********************************************************
.TP
-.B --show-net-up
+.B \-\-show-net-up
Output OpenVPN's view of the system routing table and network
adapter list to the syslog or log file after the TUN/TAP adapter
has been brought up and any routes have been added.
.\"*********************************************************
.TP
-.B --dhcp-renew
+.B \-\-dhcp-renew
Ask Windows to renew the TAP adapter lease on startup.
This option is normally unnecessary, as Windows automatically
triggers a DHCP renegotiation on the TAP adapter when it
@@ -4742,27 +4743,27 @@ Media Status property to "Always Connected", you may need this
flag.
.\"*********************************************************
.TP
-.B --dhcp-release
+.B \-\-dhcp-release
Ask Windows to release the TAP adapter lease on shutdown.
This option has the same caveats as
-.B --dhcp-renew
+.B \-\-dhcp-renew
above.
.\"*********************************************************
.TP
-.B --register-dns
+.B \-\-register-dns
Run ipconfig /flushdns and ipconfig /registerdns on
connection initiation. This is known to kick Windows into
recognizing pushed DNS servers.
.\"*********************************************************
.TP
-.B --pause-exit
+.B \-\-pause-exit
Put up a "press any key to continue" message on the console prior
to OpenVPN program exit. This option is automatically used by the
Windows explorer when OpenVPN is run on a configuration
file using the right-click explorer menu.
.\"*********************************************************
.TP
-.B --service exit-event [0|1]
+.B \-\-service exit-event [0|1]
Should be used when OpenVPN is being automatically executed by another
program in such
a context that no interaction with the user via display or keyboard
@@ -4785,26 +4786,26 @@ parameter. In any case, the controlling process can signal
causing all such OpenVPN processes to exit.
When executing an OpenVPN process using the
-.B --service
+.B \-\-service
directive, OpenVPN will probably not have a console
window to output status/error
messages, therefore it is useful to use
-.B --log
+.B \-\-log
or
-.B --log-append
+.B \-\-log-append
to write these messages to a file.
.\"*********************************************************
.TP
-.B --show-adapters
+.B \-\-show-adapters
(Standalone)
Show available TAP-Win32 adapters which can be selected using the
-.B --dev-node
+.B \-\-dev-node
option. On non-Windows systems, the
.BR ifconfig (8)
command provides similar functionality.
.\"*********************************************************
.TP
-.B --allow-nonadmin [TAP-adapter]
+.B \-\-allow-nonadmin [TAP-adapter]
(Standalone)
Set
.B TAP-adapter
@@ -4819,10 +4820,10 @@ and reloaded.
This directive can only be used by an administrator.
.\"*********************************************************
.TP
-.B --show-valid-subnets
+.B \-\-show-valid-subnets
(Standalone)
Show valid subnets for
-.B --dev tun
+.B \-\-dev tun
emulation. Since the TAP-Win32 driver
exports an ethernet interface to Windows, and since TUN devices are
point-to-point in nature, it is necessary for the TAP-Win32 driver
@@ -4832,7 +4833,7 @@ Namely, the point-to-point endpoints used in TUN device emulation
must be the middle two addresses of a /30 subnet (netmask 255.255.255.252).
.\"*********************************************************
.TP
-.B --show-net
+.B \-\-show-net
(Standalone)
Show OpenVPN's view of the system routing table and network
adapter list.
@@ -4840,12 +4841,12 @@ adapter list.
.SS PKCS#11 Standalone Options:
.\"*********************************************************
.TP
-.B --show-pkcs11-ids provider [cert_private]
+.B \-\-show-pkcs11-ids provider [cert_private]
(Standalone)
Show PKCS#11 token object list. Specify cert_private as 1
if certificates are stored as private objects.
-.B --verb
+.B \-\-verb
option can be used BEFORE this option to produce debugging information.
.\"*********************************************************
.SH SCRIPTING AND ENVIRONMENTAL VARIABLES
@@ -4855,52 +4856,52 @@ of environmental variables for use by user-defined scripts.
.SS Script Order of Execution
.\"*********************************************************
.TP
-.B --up
+.B \-\-up
Executed after TCP/UDP socket bind and TUN/TAP open.
.\"*********************************************************
.TP
-.B --tls-verify
+.B \-\-tls-verify
Executed when we have a still untrusted remote peer.
.\"*********************************************************
.TP
-.B --ipchange
+.B \-\-ipchange
Executed after connection authentication, or remote IP address change.
.\"*********************************************************
.TP
-.B --client-connect
+.B \-\-client-connect
Executed in
-.B --mode server
+.B \-\-mode server
mode immediately after client authentication.
.\"*********************************************************
.TP
-.B --route-up
+.B \-\-route-up
Executed after connection authentication, either
immediately after, or some number of seconds after
as defined by the
-.B --route-delay
+.B \-\-route-delay
option.
.\"*********************************************************
.TP
-.B --client-disconnect
+.B \-\-client-disconnect
Executed in
-.B --mode server
+.B \-\-mode server
mode on client instance shutdown.
.\"*********************************************************
.TP
-.B --down
+.B \-\-down
Executed after TCP/UDP and TUN/TAP close.
.\"*********************************************************
.TP
-.B --learn-address
+.B \-\-learn-address
Executed in
-.B --mode server
+.B \-\-mode server
mode whenever an IPv4 address/route or MAC address is added to OpenVPN's
internal routing table.
.\"*********************************************************
.TP
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
Executed in
-.B --mode server
+.B \-\-mode server
mode on new client connections, when the client is
still untrusted.
.\"*********************************************************
@@ -4924,7 +4925,7 @@ Can string remapping be disabled?
.B A:
Yes, by using the
-.B --no-name-remapping
+.B \-\-no-name-remapping
option, however this should be considered an advanced option.
Here is a brief rundown of OpenVPN's current string types and the
@@ -4940,17 +4941,17 @@ true.
Alphanumeric, underbar ('_'), dash ('-'), dot ('.'), and at
('@').
-.B --auth-user-pass username:
+.B \-\-auth-user-pass username:
Same as Common Name, with one exception: starting with OpenVPN 2.0.1,
the username is passed to the OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY plugin in its raw form,
without string remapping.
-.B --auth-user-pass password:
+.B \-\-auth-user-pass password:
Any "printable" character except CR or LF.
Printable is defined to be a character which will cause the C library
isprint() function to return true.
-.B --client-config-dir filename as derived from common name or username:
+.B \-\-client-config-dir filename as derived from common name or username:
Alphanumeric, underbar ('_'), dash ('-'), and dot ('.') except for "." or
".." as standalone strings. As of 2.0.1-rc6, the at ('@') character has
been added as well for compatibility with the common name character class.
@@ -4980,45 +4981,45 @@ which refer to different client instances.
.B bytes_received
Total number of bytes received from client during VPN session.
Set prior to execution of the
-.B --client-disconnect
+.B \-\-client-disconnect
script.
.\"*********************************************************
.TP
.B bytes_sent
Total number of bytes sent to client during VPN session.
Set prior to execution of the
-.B --client-disconnect
+.B \-\-client-disconnect
script.
.\"*********************************************************
.TP
.B common_name
The X509 common name of an authenticated client.
Set prior to execution of
-.B --client-connect, --client-disconnect,
+.B \-\-client-connect, \-\-client-disconnect,
and
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
scripts.
.\"*********************************************************
.TP
.B config
Name of first
-.B --config
+.B \-\-config
file.
Set on program initiation and reset on SIGHUP.
.\"*********************************************************
.TP
.B daemon
Set to "1" if the
-.B --daemon
+.B \-\-daemon
directive is specified, or "0" otherwise.
Set on program initiation and reset on SIGHUP.
.\"*********************************************************
.TP
.B daemon_log_redirect
Set to "1" if the
-.B --log
+.B \-\-log
or
-.B --log-append
+.B \-\-log-append
directives are specified, or "0" otherwise.
Set on program initiation and reset on SIGHUP.
.\"*********************************************************
@@ -5027,30 +5028,30 @@ Set on program initiation and reset on SIGHUP.
The actual name of the TUN/TAP device, including
a unit number if it exists.
Set prior to
-.B --up
+.B \-\-up
or
-.B --down
+.B \-\-down
script execution.
.\"*********************************************************
.TP
.B foreign_option_{n}
An option pushed via
-.B --push
+.B \-\-push
to a client which does not natively support it,
such as
-.B --dhcp-option
+.B \-\-dhcp-option
on a non-Windows system, will be recorded to this
environmental variable sequence prior to
-.B --up
+.B \-\-up
script execution.
.\"*********************************************************
.TP
.B ifconfig_broadcast
The broadcast address for the virtual
ethernet segment which is derived from the
-.B --ifconfig
+.B \-\-ifconfig
option when
-.B --dev tap
+.B \-\-dev tap
is used.
Set prior to OpenVPN calling the
.I ifconfig
@@ -5058,13 +5059,13 @@ or
.I netsh
(windows version of ifconfig) commands which
normally occurs prior to
-.B --up
+.B \-\-up
script execution.
.\"*********************************************************
.TP
.B ifconfig_local
The local VPN endpoint IP address specified in the
-.B --ifconfig
+.B \-\-ifconfig
option (first parameter).
Set prior to OpenVPN calling the
.I ifconfig
@@ -5072,15 +5073,15 @@ or
.I netsh
(windows version of ifconfig) commands which
normally occurs prior to
-.B --up
+.B \-\-up
script execution.
.\"*********************************************************
.TP
.B ifconfig_remote
The remote VPN endpoint IP address specified in the
-.B --ifconfig
+.B \-\-ifconfig
option (second parameter) when
-.B --dev tun
+.B \-\-dev tun
is used.
Set prior to OpenVPN calling the
.I ifconfig
@@ -5088,16 +5089,16 @@ or
.I netsh
(windows version of ifconfig) commands which
normally occurs prior to
-.B --up
+.B \-\-up
script execution.
.\"*********************************************************
.TP
.B ifconfig_netmask
The subnet mask of the virtual ethernet segment
that is specified as the second parameter to
-.B --ifconfig
+.B \-\-ifconfig
when
-.B --dev tap
+.B \-\-dev tap
is being used.
Set prior to OpenVPN calling the
.I ifconfig
@@ -5105,61 +5106,61 @@ or
.I netsh
(windows version of ifconfig) commands which
normally occurs prior to
-.B --up
+.B \-\-up
script execution.
.\"*********************************************************
.TP
.B ifconfig_pool_local_ip
The local
virtual IP address for the TUN/TAP tunnel taken from an
-.B --ifconfig-push
+.B \-\-ifconfig-push
directive if specified, or otherwise from
the ifconfig pool (controlled by the
-.B --ifconfig-pool
+.B \-\-ifconfig-pool
config file directive).
Only set for
-.B --dev tun
+.B \-\-dev tun
tunnels.
This option is set on the server prior to execution
of the
-.B --client-connect
+.B \-\-client-connect
and
-.B --client-disconnect
+.B \-\-client-disconnect
scripts.
.\"*********************************************************
.TP
.B ifconfig_pool_netmask
The
virtual IP netmask for the TUN/TAP tunnel taken from an
-.B --ifconfig-push
+.B \-\-ifconfig-push
directive if specified, or otherwise from
the ifconfig pool (controlled by the
-.B --ifconfig-pool
+.B \-\-ifconfig-pool
config file directive).
Only set for
-.B --dev tap
+.B \-\-dev tap
tunnels.
This option is set on the server prior to execution
of the
-.B --client-connect
+.B \-\-client-connect
and
-.B --client-disconnect
+.B \-\-client-disconnect
scripts.
.\"*********************************************************
.TP
.B ifconfig_pool_remote_ip
The remote
virtual IP address for the TUN/TAP tunnel taken from an
-.B --ifconfig-push
+.B \-\-ifconfig-push
directive if specified, or otherwise from
the ifconfig pool (controlled by the
-.B --ifconfig-pool
+.B \-\-ifconfig-pool
config file directive).
This option is set on the server prior to execution
of the
-.B --client-connect
+.B \-\-client-connect
and
-.B --client-disconnect
+.B \-\-client-disconnect
scripts.
.\"*********************************************************
.TP
@@ -5167,31 +5168,31 @@ scripts.
The maximum packet size (not including the IP header)
of tunnel data in UDP tunnel transport mode.
Set prior to
-.B --up
+.B \-\-up
or
-.B --down
+.B \-\-down
script execution.
.\"*********************************************************
.TP
.B local
The
-.B --local
+.B \-\-local
parameter.
Set on program initiation and reset on SIGHUP.
.\"*********************************************************
.TP
.B local_port
The local port number, specified by
-.B --port
+.B \-\-port
or
-.B --lport.
+.B \-\-lport.
Set on program initiation and reset on SIGHUP.
.\"*********************************************************
.TP
.B password
The password provided by a connecting client.
Set prior to
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
script execution only when the
.B via-env
modifier is specified, and deleted from the environment
@@ -5200,23 +5201,23 @@ after the script returns.
.TP
.B proto
The
-.B --proto
+.B \-\-proto
parameter.
Set on program initiation and reset on SIGHUP.
.\"*********************************************************
.TP
.B remote_{n}
The
-.B --remote
+.B \-\-remote
parameter.
Set on program initiation and reset on SIGHUP.
.\"*********************************************************
.TP
.B remote_port_{n}
The remote port number, specified by
-.B --port
+.B \-\-port
or
-.B --rport.
+.B \-\-rport.
Set on program initiation and reset on SIGHUP.
.\"*********************************************************
.TP
@@ -5224,29 +5225,29 @@ Set on program initiation and reset on SIGHUP.
The pre-existing default IP gateway in the system routing
table.
Set prior to
-.B --up
+.B \-\-up
script execution.
.\"*********************************************************
.TP
.B route_vpn_gateway
The default gateway used by
-.B --route
+.B \-\-route
options, as specified in either the
-.B --route-gateway
+.B \-\-route-gateway
option or the second parameter to
-.B --ifconfig
+.B \-\-ifconfig
when
-.B --dev tun
+.B \-\-dev tun
is specified.
Set prior to
-.B --up
+.B \-\-up
script execution.
.\"*********************************************************
.TP
.B route_{parm}_{n}
A set of variables which define each route to be added, and
are set prior to
-.B --up
+.B \-\-up
script execution.
.B parm
@@ -5265,7 +5266,7 @@ or configuration file.
Set to "init" or "restart" prior to up/down script execution.
For more information, see
documentation for
-.B --up.
+.B \-\-up.
.\"*********************************************************
.TP
.B script_type
@@ -5281,15 +5282,15 @@ Set prior to execution of any script.
The reason for exit or restart. Can be one of
.B sigusr1, sighup, sigterm, sigint, inactive
(controlled by
-.B --inactive
+.B \-\-inactive
option),
.B ping-exit
(controlled by
-.B --ping-exit
+.B \-\-ping-exit
option),
.B ping-restart
(controlled by
-.B --ping-restart
+.B \-\-ping-restart
option),
.B connection-reset
(triggered on TCP connection reset),
@@ -5303,7 +5304,7 @@ or
Client connection timestamp, formatted as a human-readable
time string.
Set prior to execution of the
-.B --client-connect
+.B \-\-client-connect
script.
.\"*********************************************************
.TP
@@ -5311,7 +5312,7 @@ script.
The duration (in seconds) of the client session which is now
disconnecting.
Set prior to execution of the
-.B --client-disconnect
+.B \-\-client-disconnect
script.
.\"*********************************************************
.TP
@@ -5319,7 +5320,7 @@ script.
Client connection timestamp, formatted as a unix integer
date/time value.
Set prior to execution of the
-.B --client-connect
+.B \-\-client-connect
script.
.\"*********************************************************
.TP
@@ -5329,7 +5330,7 @@ where
.B n
is the verification level. Only set for TLS connections. Set prior
to execution of
-.B --tls-verify
+.B \-\-tls-verify
script.
.\"*********************************************************
.TP
@@ -5340,33 +5341,38 @@ where
is the verification level. Only set for TLS connections. Set prior
to execution of
.B --tls-verify
-script.
+script. This is in the form of a hex string like "37AB46E0", which is
+suitable for doing serial-based OCSP queries (with OpenSSL, you have
+to prepend "0x" to the string). If something goes wrong while reading
+the value from the certificate it will be an empty string, so your
+code should check that.
+See the contrib/OCSP_check/OCSP_check.sh script for an example.
.\"*********************************************************
.TP
.B tun_mtu
The MTU of the TUN/TAP device.
Set prior to
-.B --up
+.B \-\-up
or
-.B --down
+.B \-\-down
script execution.
.\"*********************************************************
.TP
.B trusted_ip
Actual IP address of connecting client or peer which has been authenticated.
Set prior to execution of
-.B --ipchange, --client-connect,
+.B \-\-ipchange, \-\-client-connect,
and
-.B --client-disconnect
+.B \-\-client-disconnect
scripts.
.\"*********************************************************
.TP
.B trusted_port
Actual port number of connecting client or peer which has been authenticated.
Set prior to execution of
-.B --ipchange, --client-connect,
+.B \-\-ipchange, \-\-client-connect,
and
-.B --client-disconnect
+.B \-\-client-disconnect
scripts.
.\"*********************************************************
.TP
@@ -5375,12 +5381,12 @@ Actual IP address of connecting client or peer which has not been authenticated
yet. Sometimes used to
.B nmap
the connecting host in a
-.B --tls-verify
+.B \-\-tls-verify
script to ensure it is firewalled properly.
Set prior to execution of
-.B --tls-verify
+.B \-\-tls-verify
and
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
scripts.
.\"*********************************************************
.TP
@@ -5388,16 +5394,16 @@ scripts.
Actual port number of connecting client or peer which has not been authenticated
yet.
Set prior to execution of
-.B --tls-verify
+.B \-\-tls-verify
and
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
scripts.
.\"*********************************************************
.TP
.B username
The username provided by a connecting client.
Set prior to
-.B --auth-user-pass-verify
+.B \-\-auth-user-pass-verify
script execution only when the
.B via-env
modifier is specified.
@@ -5409,7 +5415,7 @@ where
.B n
is the verification level. Only set for TLS connections. Set prior
to execution of
-.B --tls-verify
+.B \-\-tls-verify
script. This variable is similar to
.B tls_id_{n}
except the component X509 subject fields are broken out, and
@@ -5453,30 +5459,30 @@ Like
except don't re-read configuration file, and possibly don't close and reopen TUN/TAP
device, re-read key files, preserve local IP address/port, or preserve most recently authenticated
remote IP address/port based on
-.B --persist-tun, --persist-key, --persist-local-ip,
+.B \-\-persist-tun, \-\-persist-key, \-\-persist-local-ip,
and
-.B --persist-remote-ip
+.B \-\-persist-remote-ip
options respectively (see above).
This signal may also be internally generated by a timeout condition, governed
by the
-.B --ping-restart
+.B \-\-ping-restart
option.
This signal, when combined with
-.B --persist-remote-ip,
+.B \-\-persist-remote-ip,
may be
sent when the underlying parameters of the host's network interface change
such as when the host is a DHCP client and is assigned a new IP address.
See
-.B --ipchange
+.B \-\-ipchange
above for more information.
.\"*********************************************************
.TP
.B SIGUSR2
Causes OpenVPN to display its current statistics (to the syslog
file if
-.B --daemon
+.B \-\-daemon
is used, or stdout otherwise).
.\"*********************************************************
.TP
@@ -5531,7 +5537,7 @@ If firewalls exist between
the two machines, they should be set to forward UDP port 1194
in both directions. If you do not have control over the firewalls
between the two machines, you may still be able to use OpenVPN by adding
-.B --ping 15
+.B \-\-ping 15
to each of the
.B openvpn
commands used below in the examples (this will cause each peer to send out
@@ -5600,11 +5606,11 @@ you will get a weird feedback loop.
.LP
On may:
.IP
-.B openvpn --remote june.kg --dev tun1 --ifconfig 10.4.0.1 10.4.0.2 --verb 9
+.B openvpn \-\-remote june.kg \-\-dev tun1 \-\-ifconfig 10.4.0.1 10.4.0.2 \-\-verb 9
.LP
On june:
.IP
-.B openvpn --remote may.kg --dev tun1 --ifconfig 10.4.0.2 10.4.0.1 --verb 9
+.B openvpn \-\-remote may.kg \-\-dev tun1 \-\-ifconfig 10.4.0.2 10.4.0.1 \-\-verb 9
.LP
Now verify the tunnel is working by pinging across the tunnel.
.LP
@@ -5617,17 +5623,17 @@ On june:
.B ping 10.4.0.1
.LP
The
-.B --verb 9
+.B \-\-verb 9
option will produce verbose output, similar to the
.BR tcpdump (8)
program. Omit the
-.B --verb 9
+.B \-\-verb 9
option to have OpenVPN run quietly.
.\"*********************************************************
.SS Example 2: A tunnel with static-key security (i.e. using a pre-shared secret)
First build a static key on may.
.IP
-.B openvpn --genkey --secret key
+.B openvpn \-\-genkey \-\-secret key
.LP
This command will build a random key file called
.B key
@@ -5641,11 +5647,11 @@ program.
.LP
On may:
.IP
-.B openvpn --remote june.kg --dev tun1 --ifconfig 10.4.0.1 10.4.0.2 --verb 5 --secret key
+.B openvpn \-\-remote june.kg \-\-dev tun1 \-\-ifconfig 10.4.0.1 10.4.0.2 \-\-verb 5 \-\-secret key
.LP
On june:
.IP
-.B openvpn --remote may.kg --dev tun1 --ifconfig 10.4.0.2 10.4.0.1 --verb 5 --secret key
+.B openvpn \-\-remote may.kg \-\-dev tun1 \-\-ifconfig 10.4.0.2 10.4.0.1 \-\-verb 5 \-\-secret key
.LP
Now verify the tunnel is working by pinging across the tunnel.
.LP
@@ -5667,10 +5673,10 @@ as the TLS server.
First, build a separate certificate/key pair
for both may and june (see above where
-.B --cert
+.B \-\-cert
is discussed for more info). Then construct
Diffie Hellman parameters (see above where
-.B --dh
+.B \-\-dh
is discussed for more info). You can also use the
included test files client.crt, client.key,
server.crt, server.key and ca.crt.
@@ -5683,11 +5689,11 @@ parameters you can use the included file dh1024.pem.
.LP
On may:
.IP
-.B openvpn --remote june.kg --dev tun1 --ifconfig 10.4.0.1 10.4.0.2 --tls-client --ca ca.crt --cert client.crt --key client.key --reneg-sec 60 --verb 5
+.B openvpn \-\-remote june.kg \-\-dev tun1 \-\-ifconfig 10.4.0.1 10.4.0.2 \-\-tls-client \-\-ca ca.crt \-\-cert client.crt \-\-key client.key \-\-reneg-sec 60 \-\-verb 5
.LP
On june:
.IP
-.B openvpn --remote may.kg --dev tun1 --ifconfig 10.4.0.2 10.4.0.1 --tls-server --dh dh1024.pem --ca ca.crt --cert server.crt --key server.key --reneg-sec 60 --verb 5
+.B openvpn \-\-remote may.kg \-\-dev tun1 \-\-ifconfig 10.4.0.2 10.4.0.1 \-\-tls-server \-\-dh dh1024.pem \-\-ca ca.crt \-\-cert server.crt \-\-key server.key \-\-reneg-sec 60 \-\-verb 5
.LP
Now verify the tunnel is working by pinging across the tunnel.
.LP
@@ -5700,16 +5706,16 @@ On june:
.B ping 10.4.0.1
.LP
Notice the
-.B --reneg-sec 60
+.B \-\-reneg-sec 60
option we used above. That tells OpenVPN to renegotiate
the data channel keys every minute.
Since we used
-.B --verb 5
+.B \-\-verb 5
above, you will see status information on each new key negotiation.
For production operations, a key renegotiation interval of 60 seconds
is probably too frequent. Omit the
-.B --reneg-sec 60
+.B \-\-reneg-sec 60
option to use OpenVPN's default key renegotiation interval of one hour.
.\"*********************************************************
.SS Routing:
@@ -5745,7 +5751,7 @@ over the secure tunnel (or vice versa).
In a production environment, you could put the route command(s)
in a shell script and execute with the
-.B --up
+.B \-\-up
option.
.\"*********************************************************
.SH FIREWALLS
@@ -5753,7 +5759,7 @@ OpenVPN's usage of a single UDP port makes it fairly firewall-friendly.
You should add an entry to your firewall rules to allow incoming OpenVPN
packets. On Linux 2.4+:
.IP
-.B iptables -A INPUT -p udp -s 1.2.3.4 --dport 1194 -j ACCEPT
+.B iptables -A INPUT -p udp -s 1.2.3.4 \-\-dport 1194 -j ACCEPT
.LP
This will allow incoming packets on UDP port 1194 (OpenVPN's default UDP port)
from an OpenVPN peer at 1.2.3.4.
@@ -5764,7 +5770,7 @@ address can be considered optional, since HMAC packet authentication
is a much more secure method of verifying the authenticity of
a packet source. In that case:
.IP
-.B iptables -A INPUT -p udp --dport 1194 -j ACCEPT
+.B iptables -A INPUT -p udp \-\-dport 1194 -j ACCEPT
.LP
would be adequate and would not render the host inflexible with
respect to its peer having a dynamic IP address.
@@ -5773,7 +5779,7 @@ OpenVPN also works well on stateful firewalls. In some cases, you may
not need to add any static rules to the firewall list if you are
using a stateful firewall that knows how to track UDP connections.
If you specify
-.B --ping n,
+.B \-\-ping n,
OpenVPN will be guaranteed
to send a packet to its peer at least once every
.B n