Upgrade unbound library

These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).

14 files changed, 273 insertions, 198 deletions

diff --git a/external/unbound/libunbound/python/doc/conf.py b/external/unbound/libunbound/python/doc/conf.py
index 97fca2125..1766036b9 100644
--- a/external/unbound/libunbound/python/doc/conf.py
+++ b/external/unbound/libunbound/python/doc/conf.py
@@ -82,10 +82,13 @@ pygments_style = 'sphinx'
 # Options for HTML output
 # -----------------------
 
+# The theme that the html output should use.
+html_theme = "classic"
+
 # The style sheet to use for HTML and HTML Help pages. A file of that name
 # must exist either in Sphinx' static/ path, or in one of the custom paths
 # given in html_static_path.
-html_style = 'default.css'
+#html_style = 'default.css'
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
diff --git a/external/unbound/libunbound/python/doc/examples/example1a.rst b/external/unbound/libunbound/python/doc/examples/example1a.rst
index 3c81547f2..f46cb92f4 100644
--- a/external/unbound/libunbound/python/doc/examples/example1a.rst
+++ b/external/unbound/libunbound/python/doc/examples/example1a.rst
@@ -1,26 +1,33 @@
 .. _example_resolve_name:
 
-==============================
 Resolve a name
-==============================
+==============
 
-This basic example shows how to create a context and resolve a host address (DNS record of A type).
+This basic example shows how to create a context and resolve a host address
+(DNS record of A type).
+
+Source code
+-----------
 
 ::
 
-	#!/usr/bin/python
-	import unbound
-	
-	ctx = unbound.ub_ctx()
-	ctx.resolvconf("/etc/resolv.conf")
-	
-	status, result = ctx.resolve("www.google.com")
-	if status == 0 and result.havedata:
-		print "Result.data:", result.data.address_list
-	elif status != 0:
-		print "Resolve error:", unbound.ub_strerror(status)
-
-In contrast with C API, the source code is more compact while the performance of C implementation is preserved. 
-The main advantage is that you need not take care about the deallocation and allocation of context and result structures; pyUnbound module do it automatically for you. 
-
-If only domain name is given, the :meth:`unbound.ub_ctx.resolve` looks for A records in IN class.
+    #!/usr/bin/python
+    import unbound
+
+    ctx = unbound.ub_ctx()
+    ctx.resolvconf("/etc/resolv.conf")
+
+    status, result = ctx.resolve("www.google.com")
+    if status == 0 and result.havedata:
+        print "Result.data:", result.data.address_list
+    elif status != 0:
+        print "Resolve error:", unbound.ub_strerror(status)
+
+In contrast with the C API, the source code is more compact while the
+performance of C implementation is preserved. 
+The main advantage is that you need not take care about the deallocation and
+allocation of context and result structures; pyUnbound module does it
+automatically for you. 
+
+If only domain name is given, the :meth:`unbound.ub_ctx.resolve` looks for
+A records in IN class.
diff --git a/external/unbound/libunbound/python/doc/examples/example1b.rst b/external/unbound/libunbound/python/doc/examples/example1b.rst
index ea1e6f57d..1adae2cb1 100644
--- a/external/unbound/libunbound/python/doc/examples/example1b.rst
+++ b/external/unbound/libunbound/python/doc/examples/example1b.rst
@@ -1,33 +1,37 @@
 .. _example_reverse_lookup:
 
-==============================
 Reverse DNS lookup
-==============================
+==================
 
-Reverse DNS lookup involves determining the hostname associated with a given IP address.
+Reverse DNS lookup involves determining the hostname associated with a given IP
+address.
 This example shows how reverse lookup can be done using unbound module.
 
 For the reverse DNS records, the special domain in-addr.arpa is reserved. 
-For example, a host name for the IP address 74.125.43.147 can be obtained by issuing a DNS query for the PTR record for address 147.43.125.74.in-addr.arpa.
+For example, a host name for the IP address ``74.125.43.147`` can be obtained
+by issuing a DNS query for the PTR record for address
+``147.43.125.74.in-addr.arpa.``
+
+Source code
+-----------
 
 ::
 
-	#!/usr/bin/python
-	import unbound
-	
-	ctx = unbound.ub_ctx()
-	ctx.resolvconf("/etc/resolv.conf")
-	
-	status, result = ctx.resolve(unbound.reverse("74.125.43.147") + ".in-addr.arpa.", unbound.RR_TYPE_PTR, unbound.RR_CLASS_IN)
-	if status == 0 and result.havedata:
-		print "Result.data:", result.data.domain_list
-	elif status != 0:
-		print "Resolve error:", unbound.ub_strerror(status)
-
-In order to simplify the python code, unbound module contains function which reverses the hostname components. 
-This function is defined as follows::
+    #!/usr/bin/python
+    import unbound
 
-	def reverse(domain):
-		return '.'.join([a for a in domain.split(".")][::-1])
+    ctx = unbound.ub_ctx()
+    ctx.resolvconf("/etc/resolv.conf")
 
+    status, result = ctx.resolve(unbound.reverse("74.125.43.147") + ".in-addr.arpa.", unbound.RR_TYPE_PTR, unbound.RR_CLASS_IN)
+    if status == 0 and result.havedata:
+        print "Result.data:", result.data.domain_list
+    elif status != 0:
+        print "Resolve error:", unbound.ub_strerror(status)
+
+In order to simplify the python code, unbound module contains the
+:meth:`unbound.reverse` function which reverses the hostname components.
+This function is defined as follows::
 
+    def reverse(domain):
+        return '.'.join([a for a in domain.split(".")][::-1])
diff --git a/external/unbound/libunbound/python/doc/examples/example2.rst b/external/unbound/libunbound/python/doc/examples/example2.rst
index c009ec1f5..a2bf2cbf5 100644
--- a/external/unbound/libunbound/python/doc/examples/example2.rst
+++ b/external/unbound/libunbound/python/doc/examples/example2.rst
@@ -1,41 +1,41 @@
 .. _example_setup_ctx:
 
-==============================
 Lookup from threads
-==============================
+===================
 
-This example shows how to use unbound module from a threaded program. 
-In this example, three lookup threads are created which work in background. 
-Each thread resolves different DNS record. 
+This example shows how to use unbound module from a threaded program.
+In this example, three lookup threads are created which work in background.
+Each thread resolves different DNS record.
+
+Source code
+-----------
 
 ::
 
-	#!/usr/bin/python
-	from unbound import ub_ctx, RR_TYPE_A, RR_CLASS_IN
-	from threading import Thread
-	
-	ctx = ub_ctx()
-	ctx.resolvconf("/etc/resolv.conf")
-	
-	class LookupThread(Thread):
-		def __init__(self,ctx, name):
-			Thread.__init__(self)
-			self.ctx = ctx
-			self.name = name
-
-		def run(self):
-			print "Thread lookup started:",self.name
-			status, result = self.ctx.resolve(self.name, RR_TYPE_A, RR_CLASS_IN)
-			if status == 0 and result.havedata:
-				print "  Result:",self.name,":", result.data.address_list
-	
-	threads = []
-	for name in ["www.fit.vutbr.cz","www.vutbr.cz","www.google.com"]:
-		thread = LookupThread(ctx, name)
-		thread.start()
-		threads.append(thread)
-	    
-	for thread in threads:
-		thread.join()
+    #!/usr/bin/python
+    from unbound import ub_ctx, RR_TYPE_A, RR_CLASS_IN
+    from threading import Thread
+
+    ctx = ub_ctx()
+    ctx.resolvconf("/etc/resolv.conf")
+
+    class LookupThread(Thread):
+        def __init__(self,ctx, name):
+            Thread.__init__(self)
+            self.ctx = ctx
+            self.name = name
+
+        def run(self):
+            print "Thread lookup started:",self.name
+            status, result = self.ctx.resolve(self.name, RR_TYPE_A, RR_CLASS_IN)
+            if status == 0 and result.havedata:
+                print "  Result:",self.name,":", result.data.address_list
 
+    threads = []
+    for name in ["www.fit.vutbr.cz","www.vutbr.cz","www.google.com"]:
+        thread = LookupThread(ctx, name)
+        thread.start()
+        threads.append(thread)
 
+    for thread in threads:
+        thread.join()
diff --git a/external/unbound/libunbound/python/doc/examples/example3.rst b/external/unbound/libunbound/python/doc/examples/example3.rst
index 91360335c..b0626b55f 100644
--- a/external/unbound/libunbound/python/doc/examples/example3.rst
+++ b/external/unbound/libunbound/python/doc/examples/example3.rst
@@ -1,12 +1,14 @@
 .. _example_asynch:
 
-==============================
 Asynchronous lookup
-==============================
+===================
 
 This example performs the name lookup in the background. 
 The main program keeps running while the name is resolved. 
 
+Source code
+-----------
+
 ::
 
 	#!/usr/bin/python
@@ -33,4 +35,5 @@ The main program keeps running while the name is resolved.
 	if (status != 0):
 		print "Resolve error:", unbound.ub_strerror(status)
 
-The :meth:`unbound.ub_ctx.resolve_async` method is able to pass on any Python object. In this example, we used a dictionary object `my_data`.
+The :meth:`unbound.ub_ctx.resolve_async` method is able to pass on any Python
+object. In this example, we used a dictionary object ``my_data``.
diff --git a/external/unbound/libunbound/python/doc/examples/example4.rst b/external/unbound/libunbound/python/doc/examples/example4.rst
index 996ef4ede..3b43eb85f 100644
--- a/external/unbound/libunbound/python/doc/examples/example4.rst
+++ b/external/unbound/libunbound/python/doc/examples/example4.rst
@@ -1,33 +1,35 @@
 .. _example_examine:
 
-==============================
 DNSSEC validator
-==============================
+================
 
 This example program performs DNSSEC validation of a DNS lookup.
 
+Source code
+-----------
+
 ::
 
-	#!/usr/bin/python
-	import os
-	from unbound import ub_ctx,RR_TYPE_A,RR_CLASS_IN
-	
-	ctx = ub_ctx()
-	ctx.resolvconf("/etc/resolv.conf")
-	if (os.path.isfile("keys")):
-		ctx.add_ta_file("keys") #read public keys for DNSSEC verification
-	
-	status, result = ctx.resolve("www.nic.cz", RR_TYPE_A, RR_CLASS_IN)
-	if status == 0 and result.havedata:
-	
-	    print "Result:", result.data.address_list
-	
-	    if result.secure:
-	        print "Result is secure"
-	    elif result.bogus:
-	        print "Result is bogus"
-	    else:
-	        print "Result is insecure"
+    #!/usr/bin/python
+    import os
+    from unbound import ub_ctx,RR_TYPE_A,RR_CLASS_IN
+
+    ctx = ub_ctx()
+    ctx.resolvconf("/etc/resolv.conf")
+    if (os.path.isfile("keys")):
+        ctx.add_ta_file("keys") #read public keys for DNSSEC verification
+
+    status, result = ctx.resolve("www.nic.cz", RR_TYPE_A, RR_CLASS_IN)
+    if status == 0 and result.havedata:
+
+        print "Result:", result.data.address_list
+
+        if result.secure:
+            print "Result is secure"
+        elif result.bogus:
+            print "Result is bogus"
+        else:
+            print "Result is insecure"
 
 More detailed informations can be seen in libUnbound DNSSEC tutorial `here`_.
 
diff --git a/external/unbound/libunbound/python/doc/examples/example5.rst b/external/unbound/libunbound/python/doc/examples/example5.rst
index 0a31d9a57..9262014bb 100644
--- a/external/unbound/libunbound/python/doc/examples/example5.rst
+++ b/external/unbound/libunbound/python/doc/examples/example5.rst
@@ -1,13 +1,17 @@
 .. _example_resolver_only:
 
-==============================
 Resolver only
-==============================
+=============
 
 This example program shows how to perform DNS resolution only.
 Unbound contains two basic modules: resolver and validator.
-In case, the validator is not necessary, the validator module can be turned off using "module-config" option.
-This option contains a list of module names separated by the space char. This list determined which modules should be employed and in what order.
+In case, the validator is not necessary, the validator module can be turned off
+using "module-config" option.
+This option contains a list of module names separated by the space char. This
+list determined which modules should be employed and in what order.
+
+Source code
+-----------
 
 ::
 
@@ -25,5 +29,6 @@ This option contains a list of module names separated by the space char. This li
 	    print "Result:", result.data.address_list
 
 .. note::
-   The :meth:`unbound.ub_ctx.set_option` method must be used before the first resolution (i.e. before :meth:`unbound.ub_ctx.resolve` or :meth:`unbound.ub_ctx.resolve_async` call). 
-
+   The :meth:`unbound.ub_ctx.set_option` method must be used before the first
+   resolution (i.e. before :meth:`unbound.ub_ctx.resolve` or
+   :meth:`unbound.ub_ctx.resolve_async` call).
diff --git a/external/unbound/libunbound/python/doc/examples/example6.rst b/external/unbound/libunbound/python/doc/examples/example6.rst
index 478e13909..6fde8b25f 100644
--- a/external/unbound/libunbound/python/doc/examples/example6.rst
+++ b/external/unbound/libunbound/python/doc/examples/example6.rst
@@ -1,11 +1,13 @@
 .. _example_localzone:
 
-==============================
 Local zone manipulation
-==============================
+=======================
 
-This example program shows how to define local zone containing custom DNS records.
+This example program shows how to define local zone containing custom DNS
+records.
 
-..	literalinclude:: example6-1.py
-	:language: python
+Source code
+-----------
 
+.. literalinclude:: example6-1.py
+    :language: python
diff --git a/external/unbound/libunbound/python/doc/examples/example7.rst b/external/unbound/libunbound/python/doc/examples/example7.rst
index d4050215e..2f48c8f0f 100644
--- a/external/unbound/libunbound/python/doc/examples/example7.rst
+++ b/external/unbound/libunbound/python/doc/examples/example7.rst
@@ -1,18 +1,33 @@
 .. _example_idna:
 
-=================================================
 Internationalized domain name support
-=================================================
+=====================================
 
 Unlike the libUnbound, pyUnbound is able to handle IDN queries.
 
-..	literalinclude:: example7-1.py
-	:language: python
+Automatic IDN DNAME conversion
+-------------------------------
 
-If we use unicode string in :meth:`unbound.ub_ctx.resolve` method, the IDN DNAME conversion (if it is necessary) is performed on background.
+If we use unicode string in :meth:`unbound.ub_ctx.resolve` method,
+the IDN DNAME conversion (if it is necessary) is performed on background.
 
-..	literalinclude:: example7-2.py
-	:language: python
+Source code
+...........
 
-The :class:`unbound.ub_data` class contains attributes suffix which converts the dname to UTF string. These attributes have the '_idn' suffix.
-Apart from this aproach, two conversion functions exist (:func:`unbound.idn2dname` and :func:`unbound.dname2idn`).
+.. literalinclude:: example7-1.py
+    :language: python
+
+IDN converted attributes
+------------------------
+
+The :class:`unbound.ub_data` class contains attributes suffix which converts
+the dname to UTF string. These attributes have the ``_idn`` suffix.
+
+Apart from this aproach, two conversion functions exist
+(:func:`unbound.idn2dname` and :func:`unbound.dname2idn`).
+
+Source code
+...........
+
+.. literalinclude:: example7-2.py
+    :language: python
diff --git a/external/unbound/libunbound/python/doc/examples/example8.rst b/external/unbound/libunbound/python/doc/examples/example8.rst
index 8cdfcdc0a..16c140475 100644
--- a/external/unbound/libunbound/python/doc/examples/example8.rst
+++ b/external/unbound/libunbound/python/doc/examples/example8.rst
@@ -1,28 +1,34 @@
 .. _example_mxlookup:
 
-=================================================
 Lookup for MX and NS records
-=================================================
+============================
 
-The pyUnbound extension provides functions which are able to encode RAW RDATA produces by unbound resolver (see :class:`unbound.ub_data`).
+The pyUnbound extension provides functions which are able to encode RAW RDATA
+produces by unbound resolver (see :class:`unbound.ub_data`).
 
-..	literalinclude:: example8-1.py
-	:language: python
+Source code
+-----------
 
-Previous example produces following output::
+.. literalinclude:: example8-1.py
+    :language: python
 
-	Result:
-		raw data: 00 0F 05 6D 61 69 6C 34 03 6E 69 63 02 63 7A 00;00 14 02 6D 78 05 63 7A 6E 69 63 03 6F 72 67 00;00 0A 04 6D 61 69 6C 03 6E 69 63 02 63 7A 00
-		priority:15 address: mail4.nic.cz.
-		priority:20 address: mx.cznic.org.
-		priority:10 address: mail.nic.cz.
+Output
+------
 
-	Result:
-		raw data: D9 1F CD 32
-		address: 217.31.205.50
+The previous example produces the following output::
 
-	Result:
-		raw data: 01 61 02 6E 73 03 6E 69 63 02 63 7A 00;01 65 02 6E 73 03 6E 69 63 02 63 7A 00;01 63 02 6E 73 03 6E 69 63 02 63 7A 00
-		host: a.ns.nic.cz.
-		host: e.ns.nic.cz.
-		host: c.ns.nic.cz.
+    Result:
+        raw data: 00 0F 05 6D 61 69 6C 34 03 6E 69 63 02 63 7A 00;00 14 02 6D 78 05 63 7A 6E 69 63 03 6F 72 67 00;00 0A 04 6D 61 69 6C 03 6E 69 63 02 63 7A 00
+        priority:15 address: mail4.nic.cz.
+        priority:20 address: mx.cznic.org.
+        priority:10 address: mail.nic.cz.
+
+    Result:
+        raw data: D9 1F CD 32
+        address: 217.31.205.50
+
+    Result:
+        raw data: 01 61 02 6E 73 03 6E 69 63 02 63 7A 00;01 65 02 6E 73 03 6E 69 63 02 63 7A 00;01 63 02 6E 73 03 6E 69 63 02 63 7A 00
+        host: a.ns.nic.cz.
+        host: e.ns.nic.cz.
+        host: c.ns.nic.cz.
diff --git a/external/unbound/libunbound/python/doc/examples/index.rst b/external/unbound/libunbound/python/doc/examples/index.rst
index c2c9cf457..283261652 100644
--- a/external/unbound/libunbound/python/doc/examples/index.rst
+++ b/external/unbound/libunbound/python/doc/examples/index.rst
@@ -1,14 +1,16 @@
 Examples
-==============================
+========
 
-Here you can find several examples which utilizes the unbound library in Python environment. 
-Unbound is a caching validator and resolver and can be linked into an application, as a library where can answer DNS queries for the application. 
+Here you can find several examples which utilizes the unbound library in Python
+environment. Unbound is a caching validator and resolver and can be linked into
+an application, as a library where can answer DNS queries for the application.
 This set of examples shows how to use the functions from Python environment.
 
-`Tutorials`
+Tutorials
+---------
 
 .. toctree::
-	:maxdepth: 1
-	:glob:
+    :maxdepth: 1
+    :glob:
 
-	example*
+    example*
diff --git a/external/unbound/libunbound/python/doc/install.rst b/external/unbound/libunbound/python/doc/install.rst
index a073a5c66..bb3118984 100644
--- a/external/unbound/libunbound/python/doc/install.rst
+++ b/external/unbound/libunbound/python/doc/install.rst
@@ -1,31 +1,38 @@
 Installation
-===================================
+============
 
-**Prerequisites**
+Prerequisites
+-------------
 
 Python 2.4 or higher, SWIG 1.3 or higher, GNU make
 
-**Compiling**
+Compiling
+---------
 
 After downloading, you can compile the pyUnbound library by doing::
 
-	> tar -xzf unbound-x.x.x-py.tar.gz
-	> cd unbound-x.x.x
-	> ./configure --with-pyunbound
-	> make
+    > tar -xzf unbound-x.x.x-py.tar.gz
+    > cd unbound-x.x.x
+    > ./configure --with-pyunbound
+    > make
 
-You may want to --with-pythonmodule as well if you want to use python as
-a module in the resolver.
+You may want to enable ``--with-pythonmodule`` as well if you want to use
+python as a module in the resolver.
 
-You need GNU make to compile sources; SWIG and Python devel libraries to compile extension module. 
+You need ``GNU make`` to compile sources; ``SWIG`` and ``Python devel``
+libraries to compile extension module. 
 
 
-**Testing**
+Testing
+-------
 
-If the compilation is successful, you can test the python LDNS extension module by::
+If the compilation is successful, you can test the python LDNS extension module
+by::
 
-	> cd contrib/python
-	> make testenv
-	> ./dns-lookup.py
+    > cd contrib/python
+    > make testenv
+    > ./dns-lookup.py
 
-You may want to make install in the main directory since make testenv is for debugging.  In contrib/examples you can find simple applications written in Python using the Unbound extension.
+You may want to ``make install`` in the main directory since ``make testenv``
+is for debugging.  In contrib/examples you can find simple applications written
+in Python using the Unbound extension.
diff --git a/external/unbound/libunbound/python/doc/intro.rst b/external/unbound/libunbound/python/doc/intro.rst
index f751f54c0..e490d2c6f 100644
--- a/external/unbound/libunbound/python/doc/intro.rst
+++ b/external/unbound/libunbound/python/doc/intro.rst
@@ -1,39 +1,58 @@
 Introduction
-===================================
-
-**Unbound**
-
-	`Unbound`_  is  an implementation of a DNS resolver, that performs caching and DNSSEC validation.
-	Together with unbound, the libunbound library is provided.
-	This library can be used to convert hostnames to ip addresses, and back, as well as obtain other information. 
-	Since the resolver allows to specify the class and type of a query (A record, NS, MX, ...), this library offers powerful resolving tool. 
-	The library also performs public-key validation of results with DNSSEC.
-	
-	.. _Unbound: http://www.unbound.net/documentation
-
-**pyUnbound**
-
-	The pyUnbound is an extension module for Python which provides an object-oriented interface to libunbound. 
-	It is the first Python module which offers thread-safe caching resolver.
-	
-	The interface was designed with the emphasis on the simplicity of use.
-	There are two main classes :class:`unbound.ub_ctx` (a validation and resolution context) and :class:`unbound.ub_result` which contains the validation and resolution results.
-	The objects are thread-safe, and a context can be used in non-threaded as well as threaded environment. 
-	Resolution can be performed blocking and non-blocking (i.e. asynchronous).  
-	The asynchronous method returns from the call immediately, so that processing can go on, while the results become available later.
-
-**Features**
-	* customizable caching validation resolver for synchronous and asynchronous lookups
-	* easy to use object interface
-	* easy to integrate extension module
-	* designed for thread environment (i.e. thread-safe)
-	* allows define and customize of local zone and its RR's during the operation (i.e. without restart)
-	* includes encoding functions to simplify the results retrieval
-	* Internationalized domain name (`IDN`_) support
-
-	.. _IDN: http://en.wikipedia.org/wiki/Internationalized_domain_name
-
-**Application area**
-	* DNS-based applications performing DNS lookups; the caching resolver can reduce overhead
-	* Applications where the validation of DNS records is required
-	* Great solution for customizable and dynamic DNS-based white/blacklists (spam rejection, connection rejection, ...) using the dynamic local zone manipulation
+============
+
+Unbound
+-------
+
+`Unbound`_  is  an implementation of a DNS resolver, that performs caching and
+DNSSEC validation.
+Together with unbound, the libunbound library is provided.
+This library can be used to convert hostnames to ip addresses, and back, as
+well as obtain other information.
+Since the resolver allows to specify the class and type of a query (A record,
+NS, MX, ...), this library offers powerful resolving tool.
+The library also performs public-key validation of results with DNSSEC.
+
+.. _Unbound: http://www.unbound.net/documentation
+
+pyUnbound
+---------
+
+The pyUnbound is an extension module for Python which provides an
+object-oriented interface to libunbound. 
+It is the first Python module which offers thread-safe caching resolver.
+
+The interface was designed with the emphasis on the simplicity of use.
+There are two main classes :class:`unbound.ub_ctx` (a validation and resolution
+context) and :class:`unbound.ub_result` which contains the validation and
+resolution results.
+The objects are thread-safe, and a context can be used in non-threaded as well
+as threaded environment.
+Resolution can be performed blocking and non-blocking (i.e. asynchronous).
+The asynchronous method returns from the call immediately, so that processing
+can go on, while the results become available later.
+
+Features
+--------
+
+* Customizable caching validation resolver for synchronous and asynchronous
+  lookups
+* Easy to use object interface
+* Easy to integrate extension module
+* Designed for thread environment (i.e. thread-safe)
+* Allows define and customize of local zone and its RR's during the operation
+  (i.e. without restart)
+* Includes encoding functions to simplify the results retrieval
+* Internationalized domain name (`IDN`_) support
+
+.. _IDN: http://en.wikipedia.org/wiki/Internationalized_domain_name
+
+Application area
+----------------
+
+* DNS-based applications performing DNS lookups; the caching resolver can
+  reduce overhead
+* Applications where the validation of DNS records is required
+* Great solution for customizable and dynamic DNS-based white/blacklists (spam
+  rejection, connection rejection, ...) using the dynamic local zone
+  manipulation
diff --git a/external/unbound/libunbound/python/libunbound.i b/external/unbound/libunbound/python/libunbound.i
index 50a9b67ac..84a536929 100644
--- a/external/unbound/libunbound/python/libunbound.i
+++ b/external/unbound/libunbound/python/libunbound.i
@@ -945,7 +945,7 @@ int _ub_resolve_async(struct ub_ctx* ctx, char* name, int rrtype, int rrclass, v
            :param idnname: (unicode string) IDN name
            :returns: (string) domain name
         """
-        return '.'.join([encodings.idna.ToASCII(a) for a in idnname.split('.')])
+        return '.'.join([encodings.idna.ToASCII(a) if a else '' for a in idnname.split('.')])
 
     def dname2idn(name):
         """Converts canonic domain name in IDN format to unicode string