diff --git a/Doc/library/ipaddr.rst b/Doc/library/ipaddr.rst
new file mode 100644
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--- /dev/null
+++ b/Doc/library/ipaddr.rst
@@ -0,0 +1,327 @@
+
+:mod:`ipaddr` --- IP address manipulation library
+=================================================
+
+.. module:: ipaddr
+   :synopsis: IPv4 and IPv6 network address manipulation classes.
+.. moduleauthor:: Google, Inc.
+.. sectionauthor:: Gregory P. Smith <greg@krypto.org>
+
+
+.. versionadded:: 2.7
+
+.. index::
+   single: IP address, IPv4, IPv6, netmask
+
+This module implements classes for working with IP host and network addresses,
+both IPv4 and IPv6.
+
+
+.. function:: IP(ipaddr)
+
+   Take an IP string or int and return an object of the correct type.
+   Returns an :class:`IPv4` or :class:`IPv6` object.
+
+   The ``ipaddr`` parameter must be a string or integer representing the IP
+   address.  Either IPv4 or IPv6 addresses may be supplied.  Integers less
+   than 2**32 will be considered to be IPv4.
+
+   Raises :exc:`ValueError` if the ipaddr passed is not either an IPv4 or an
+   IPv6 address.
+
+
+.. function:: collapse_address_list(addresses)
+
+   Collapses a sequence of :class:`IPv4` or :class:`IPv6` objects into
+   the most concise representation.  Returns a list of :class:`IPv4`
+   or :class:`IPv6` objects.
+
+Example usage::
+
+   >>> collapse_address_list([IPv4('1.1.0.0/24'), IPv4('1.1.1.0/24')])
+   [IPv4('1.1.0.0/23')]
+
+
+.. class:: BaseIP()
+
+   A generic IP address object.  This base class defines the API and contains
+   common code.  Most authors should either use the :func:`IP` function or
+   create :class:`IPv4` or :class:`IPv6` objects directly rather than using
+   this base class.
+
+
+   IP address objects support the following python operators:
+   ``=``, ``!=``, ``<``, ``>``, ``<=``, ``>=``, and ``in``.
+
+   An IP address object may be used as a sequence index or as a hash key
+   and can be converted back to an integer representation using ``int()``.
+   It may also be used as a sequence that yeilds the string
+   representation of every IP address within the object's subnet.
+
+
+   The following properties are available on all IP address objects:
+
+   .. data:: broadcast
+
+      Integer representation of the broadcast address.  Read only.
+
+   .. data:: broadcast_ext
+
+      Dotted decimal or colon string version of the broadcast address.  Read only.
+
+   .. data:: hostmask
+
+      Integer representation of the hostmask.  Read only.
+
+   .. data:: hostmask_ext
+
+      Dotted decimal or colon string version of the hostmask.  Read only.
+
+   .. data:: ip
+
+      Integer representation of the IP address.  Read only.
+
+   .. data:: ip_ext
+
+      Dotted decimal or colon string version of the IP address.  Read only.
+
+   .. data:: ip_ext_full
+
+      Canonical string version of the IP address.  Read only.
+
+   .. data:: is_loopback
+
+      True if the address is a loopback address as defined in IPv4 :rfc:`3330`
+      or IPv6 :rfc:`2373` section 2.5.3.
+
+   .. data:: is_link_local
+
+      True if the address is a link-local address as defined in IPv4 :rfc:`3927`
+      or IPv6 :rfc:`4291`.
+
+   .. data:: is_multicast
+
+      True if the address is reserved for multicast use.
+      See IPv4 :rfc:`3171` or IPv6 :rfc:`2373` section 2.7 for details.
+
+   .. data:: is_private
+
+      True if the address is reserved for private networks as defined in
+      IPv4 :rfc:`1918` or IPv6 :rfc:`4193`.
+
+   .. data:: netmask
+
+      Integer representation of the netmask.  Read only.
+
+   .. data:: netmask_ext
+
+      Dotted decimal or colon string version of the netmask.  Read only.
+
+   .. data:: network
+
+      Integer representation of the network.  Read only.
+
+   .. data:: network_ext
+
+      Dotted decimal or colon string version of the network.  Read only.
+
+   .. data:: numhosts
+
+      Number of hosts in the current subnet.  Read only.
+
+   .. data:: packed
+
+      The packed network byte order representation of this network address.  Read only.
+
+   .. data:: prefixlen
+
+      A property to get and set the prefix length.  Readable and writeable.
+
+   .. data:: version
+
+      Integer IP version number.  Read only.
+
+
+   The following methods are available on all IP address objects:
+
+   .. method:: address_exclude(other)
+
+      Remove an address from within a larger block.
+      Returns a sorted list of IP address objects representing networks.
+
+   Examples::
+
+      >>> addr1 = IP('10.1.1.0/24')
+      >>> addr2 = IP('10.1.1.0/26')
+      >>> addr1.address_exclude(addr2)
+      [IP('10.1.1.64/26'), IP('10.1.1.128/25')]
+
+      >>> addr1 = IP('::1/32')
+      >>> addr2 = IP('::1/128')
+      >>> addr1.address_exclude(addr2)
+      [IP('::0/128'), IP('::2/127'), IP('::4/126'), IP('::8/125'),
+       ... IP('0:0:8000::/33')]
+
+      Raises :exc:`ValueError` if `other` is not completely contained by self.
+
+
+   .. method:: compare_networks(other)
+
+      Compare this IP object's network to another IP network.
+      Returns -1, 0 or 1.
+
+      This compares the integer representation of the network addresses.
+      The host bits are not considered by this method.
+      If you want to compare host bits, you can use ``host_a.ip < host_b.ip``.
+
+      If the IP versions of self and other are the same, returns:
+
+      -1 if self < other
+        eg: IPv4('1.1.1.0/24') < IPv4('1.1.2.0/24')
+
+        IPv6('1080::200C:417A') < IPv6('1080::200B:417B')
+
+      0 if self == other
+        eg: IPv4('1.1.1.1/24') == IPv4('1.1.1.2/24')
+
+        IPv6('1080::200C:417A/96') == IPv6('1080::200C:417B/96')
+
+      1 if self > other
+        eg: IPv4('1.1.1.0/24') > IPv4('1.1.0.0/24')
+
+        IPv6('1080::1:200C:417A/112') > IPv6('1080::0:200C:417A/112')
+
+      If the IP versions of self and other are different, returns:
+
+      -1 if self.version < other.version
+        eg: IPv4('10.0.0.1/24') < IPv6('::1/128')
+
+      1 if self.version > other.version
+        eg: IPv6('::1/128') > IPv4('255.255.255.0/24')
+
+
+   .. method:: subnet(prefixlen_diff=1)
+
+      Returns a list of subnets which when joined make up the current subnet.
+
+      The optional ``prefixlen_diff`` argument specifies how many bits the prefix
+      length should be increased by.  Given a /24 network and prefixlen_diff=3,
+      for example, 8 subnets of size /27 will be returned.
+
+      If called on a host IP address rather than a network, a list containing
+      the host itself will be returned.
+
+      Raises :exc:`PrefixlenDiffInvalidError` if the prefixlen_diff is out of
+      range.
+
+
+   .. method:: supernet(prefixlen_diff=1)
+
+      Returns a single IP object representing the supernet containing the
+      current network.
+
+      The optional ``prefixlen_diff`` argument specifies how many bits the prefix
+      length should be decreased by.  Given a /24 network and prefixlen_diff=3,
+      for example, a supernet with a 21 bit netmask is returned.
+
+      Raises :exc:`PrefixlenDiffInvalidError` if the prefixlen_diff is out of
+      range.
+
+
+.. class:: IPv4()
+
+   This class represents and manipulates 32-bit IPv4 addresses.
+
+   Attributes::
+
+      # These examples for IPv4('1.2.3.4/27')
+      .ip: 16909060
+      .ip_ext: '1.2.3.4'
+      .ip_ext_full: '1.2.3.4'
+      .network: 16909056
+      .network_ext: '1.2.3.0'
+      .hostmask: 31 (0x1F)
+      .hostmask_ext: '0.0.0.31'
+      .broadcast: 16909087 (0x102031F)
+      .broadcast_ext: '1.2.3.31'
+      .netmask: 4294967040 (0xFFFFFFE0)
+      .netmask_ext: '255.255.255.224'
+      .prefixlen: 27
+
+
+.. class:: IPv6()
+
+   This class respresents and manipulates 128-bit IPv6 addresses.
+
+   Attributes::
+
+      # These examples are for IPv6('2001:658:22A:CAFE:200::1/64')
+      .ip: 42540616829182469433547762482097946625
+      .ip_ext: '2001:658:22a:cafe:200::1'
+      .ip_ext_full: '2001:0658:022a:cafe:0200:0000:0000:0001'
+      .network: 42540616829182469433403647294022090752
+      .network_ext: '2001:658:22a:cafe::'
+      .hostmask: 18446744073709551615
+      .hostmask_ext: '::ffff:ffff:ffff:ffff'
+      .broadcast: 42540616829182469451850391367731642367
+      .broadcast_ext: '2001:658:22a:cafe:ffff:ffff:ffff:ffff'
+      .netmask: 340282366920938463444927863358058659840
+      .netmask_ext: 64
+      .prefixlen: 64
+
+   .. data:: is_site_local
+
+      True if the address was reserved as site-local in :rfc:`3513` section 2.5.6.
+
+      .. note::
+
+         The IPv6 site-local address space has been deprecated by :rfc:`3879`.
+         Use :data:`is_private` to test if this address is in the space of
+         unique local addresses as defined by :rfc:`4193`.
+
+   .. data:: is_unspecified
+
+      True if this is the unspecified address as defined in :rfc:`2373` section 2.5.2.
+
+
+The following exceptions are defined by this module:
+
+.. exception:: Error
+
+   Base class for all exceptions defined in this module.
+
+.. exception:: IPTypeError
+
+   Tried to perform a v4 action on v6 object or vice versa.
+
+.. exception:: IPAddressExclusionError
+
+   An Error we should never see occurred in address exclusion.
+
+.. exception:: IPv4IpValidationError
+
+   Raised when an IPv4 address is invalid.
+
+.. exception:: IPv4NetmaskValidationError
+
+   Raised when a netmask is invalid.
+
+.. exception:: IPv6IpValidationError
+
+   Raised when an IPv6 address is invalid.
+
+.. exception:: IPv6NetmaskValidationError
+
+   Raised when an IPv6 netmask is invalid.
+
+.. exception:: PrefixlenDiffInvalidError
+
+   Raised when :meth:`BaseIP.subnet` or :meth:`BaseIP.supernet` is called with a bad
+   ``prefixlen_diff``.
+
+
+.. seealso::
+
+   http://code.google.com/p/ipaddr-py/
+      The original source of this module and a place to download it as
+      a package for use on earlier versions of Python.
diff --git a/Lib/ipaddr.py b/Lib/ipaddr.py
new file mode 100644
index 0000000..c95a814
--- /dev/null
+++ b/Lib/ipaddr.py
@@ -0,0 +1,1365 @@
+# Copyright 2007 Google Inc.
+#  Licensed to PSF under a Contributor Agreement.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied. See the License for the specific language governing
+# permissions and limitations under the License.
+#
+# See also: http://code.google.com/p/ipaddr-py/
+
+"""An IPv4/IPv6 manipulation library in Python.
+
+This library is used to create/poke/manipulate IPv4 and IPv6 addresses
+and prefixes.
+
+"""
+
+__version__ = '1.0.2'
+
+import struct
+
+class Error(Exception):
+
+    """Base class for exceptions."""
+
+
+class IPTypeError(Error):
+
+    """Tried to perform a v4 action on v6 object or vice versa."""
+
+
+class IPAddressExclusionError(Error):
+
+    """An Error we should never see occurred in address exclusion."""
+
+
+class IPv4IpValidationError(Error):
+
+    """Raised when an IPv4 address is invalid."""
+
+    def __init__(self, ip):
+        Error.__init__(self)
+        self.ip = ip
+
+    def __str__(self):
+        return repr(self.ip) + ' is not a valid IPv4 address'
+
+
+class IPv4NetmaskValidationError(Error):
+
+    """Raised when a netmask is invalid."""
+
+    def __init__(self, netmask):
+        Error.__init__(self)
+        self.netmask = netmask
+
+    def __str__(self):
+        return repr(self.netmask) + ' is not a valid IPv4 netmask'
+
+
+class IPv6IpValidationError(Error):
+
+    """Raised when an IPv6 address is invalid."""
+
+    def __init__(self, ip):
+        Error.__init__(self)
+        self.ip = ip
+
+    def __str__(self):
+        return repr(self.ip) + ' is not a valid IPv6 address'
+
+
+class IPv6NetmaskValidationError(Error):
+
+    """Raised when an IPv6 netmask is invalid."""
+
+    def __init__(self, netmask):
+        Error.__init__(self)
+        self.netmask = netmask
+
+    def __str__(self):
+        return repr(self.netmask) + ' is not a valid IPv6 netmask'
+
+
+class PrefixlenDiffInvalidError(Error):
+
+    """Raised when Sub/Supernets is called with a bad prefixlen_diff."""
+
+    def __init__(self, error_str):
+        Error.__init__(self)
+        self.error_str = error_str
+
+
+def IP(ipaddr):
+    """Take an IP string/int and return an object of the correct type.
+
+    Args:
+        ipaddr: A string or integer, the IP address.  Either IPv4 or
+          IPv6 addresses may be supplied; integers less than 2**32 will
+          be considered to be IPv4.
+
+    Returns:
+        An IPv4 or IPv6 object.
+
+    Raises:
+        ValueError: if the string passed isn't either a v4 or a v6
+          address.
+
+    """
+
+    try:
+        return IPv4(ipaddr)
+    except (IPv4IpValidationError, IPv4NetmaskValidationError):
+        pass
+
+    try:
+        return IPv6(ipaddr)
+    except (IPv6IpValidationError, IPv6NetmaskValidationError):
+        pass
+
+    raise ValueError('%r does not appear to be an IPv4 or IPv6 address' %
+                     ipaddr)
+
+
+def _collapse_address_list_recursive(addresses):
+    """Loops through the addresses, collapsing concurrent netblocks.
+
+    Example:
+
+        ip1 = IPv4('1.1.0.0/24')
+        ip2 = IPv4('1.1.1.0/24')
+        ip3 = IPv4('1.1.2.0/24')
+        ip4 = IPv4('1.1.3.0/24')
+        ip5 = IPv4('1.1.4.0/24')
+        ip6 = IPv4('1.1.0.1/22')
+
+        _collapse_address_list_recursive([ip1, ip2, ip3, ip4, ip5, ip6]) ->
+          [IPv4('1.1.0.0/22'), IPv4('1.1.4.0/24')]
+
+        This shouldn't be called directly; it is called via
+          collapse_address_list([]).
+
+    Args:
+        addresses: A list of IPv4 or IPv6 objects.
+
+    Returns:
+        A list of IPv4 or IPv6 objects depending on what we were passed.
+
+    """
+    ret_array = []
+    optimized = False
+
+    for cur_addr in addresses:
+        if not ret_array:
+            ret_array.append(cur_addr)
+            continue
+        if cur_addr in ret_array[-1]:
+            optimized = True
+        elif cur_addr == ret_array[-1].supernet().subnet()[1]:
+            ret_array.append(ret_array.pop().supernet())
+            optimized = True
+        else:
+            ret_array.append(cur_addr)
+
+    if optimized:
+        return _collapse_address_list_recursive(ret_array)
+
+    return ret_array
+
+
+def collapse_address_list(addresses):
+    """Collapse a list of IP objects.
+
+    Example:
+        collapse_address_list([IPv4('1.1.0.0/24'), IPv4('1.1.1.0/24')]) ->
+          [IPv4('1.1.0.0/23')]
+
+    Args:
+        addresses: A list of IPv4 or IPv6 objects.
+
+    Returns:
+        A list of IPv4 or IPv6 objects depending on what we were passed.
+
+    """
+    return _collapse_address_list_recursive(
+        sorted(addresses, key=BaseIP._get_networks_key))
+
+
+# Test whether this Python implementation supports byte objects that
+# are not identical to str ones.
+# We need to exclude platforms where bytes == str so that we can
+# distinguish between packed representations and strings, for example
+# b'12::' (the IPv4 address 49.50.58.58) and '12::' (an IPv6 address).
+try:
+    _compat_has_real_bytes = bytes != str
+except NameError: # <Python2.6
+    _compat_has_real_bytes = False
+
+
+class BaseIP(object):
+
+    """A generic IP object.
+
+    This IP class contains most of the methods which are used by
+    the IPv4 and IPv6 classes.
+
+    """
+
+    def __getitem__(self, n):
+        if n >= 0:
+            if self.network + n > self.broadcast:
+                raise IndexError
+            return self._string_from_ip_int(self.network + n)
+        else:
+            if self.broadcast + n < self.network:
+                raise IndexError
+            return self._string_from_ip_int(self.broadcast + n)
+
+    def __lt__(self, other):
+        try:
+            return (self.version < other.version
+                    or self.ip < other.ip
+                    or self.netmask < other.netmask)
+        except AttributeError:
+            return NotImplemented
+
+    def __gt__(self, other):
+        try:
+            return (self.version > other.version
+                    or self.ip > other.ip
+                    or self.netmask > other.netmask)
+        except AttributeError:
+            return NotImplemented
+
+    def __eq__(self, other):
+        try:
+            return (self.version == other.version
+                    and self.ip == other.ip
+                    and self.netmask == other.netmask)
+        except AttributeError:
+            return NotImplemented
+
+    def __ne__(self, other):
+        eq = self.__eq__(other)
+        if eq is NotImplemented:
+            return NotImplemented
+        return not eq
+
+    def __le__(self, other):
+        gt = self.__gt__(other)
+        if gt is NotImplemented:
+            return NotImplemented
+        return not gt
+
+    def __ge__(self, other):
+        lt = self.__lt__(other)
+        if lt is NotImplemented:
+            return NotImplemented
+        return not lt
+
+    def __repr__(self):
+        return '%s(%r)' % (self.__class__.__name__, str(self))
+
+    def __index__(self):
+        return self.ip
+
+    def __int__(self):
+        return self.ip
+
+    def __hex__(self):
+        return hex(int(self))
+
+    def address_exclude(self, other):
+        """Remove an address from a larger block.
+
+        For example:
+
+            addr1 = IP('10.1.1.0/24')
+            addr2 = IP('10.1.1.0/26')
+            addr1.address_exclude(addr2) =
+                [IP('10.1.1.64/26'), IP('10.1.1.128/25')]
+
+        or IPv6:
+
+            addr1 = IP('::1/32')
+            addr2 = IP('::1/128')
+            addr1.address_exclude(addr2) = [IP('::0/128'),
+                IP('::2/127'),
+                IP('::4/126'),
+                IP('::8/125'),
+                ...
+                IP('0:0:8000::/33')]
+
+        Args:
+            other: An IP object of the same type.
+
+        Returns:
+            A sorted list of IP objects addresses which is self minus
+            other.
+
+        Raises:
+            IPTypeError: If self and other are of difffering address
+              versions.
+            IPAddressExclusionError: There was some unknown error in the
+              address exclusion process.  This likely points to a bug
+              elsewhere in this code.
+            ValueError: If other is not completely contained by self.
+
+        """
+        if not self.version == other.version:
+            raise IPTypeError("%s and %s aren't of the same version" % (
+                str(self), str(other)))
+
+        if other not in self:
+            raise ValueError('%s not contained in %s' % (str(other),
+                                                         str(self)))
+
+        ret_addrs = []
+
+        # Make sure we're comparing the network of other.
+        other = IP(other.network_ext + '/' + str(other.prefixlen))
+
+        s1, s2 = self.subnet()
+        while s1 != other and s2 != other:
+            if other in s1:
+                ret_addrs.append(s2)
+                s1, s2 = s1.subnet()
+            elif other in s2:
+                ret_addrs.append(s1)
+                s1, s2 = s2.subnet()
+            else:
+                # If we got here, there's a bug somewhere.
+                raise IPAddressExclusionError('Error performing exclusion: '
+                                              's1: %s s2: %s other: %s' %
+                                              (str(s1), str(s2), str(other)))
+        if s1 == other:
+            ret_addrs.append(s2)
+        elif s2 == other:
+            ret_addrs.append(s1)
+        else:
+            # If we got here, there's a bug somewhere.
+            raise IPAddressExclusionError('Error performing exclusion: '
+                                          's1: %s s2: %s other: %s' %
+                                          (str(s1), str(s2), str(other)))
+
+        return sorted(ret_addrs, key=BaseIP._get_networks_key)
+
+    def compare_networks(self, other):
+        """Compare two IP objects.
+
+        This is only concerned about the comparison of the integer
+        representation of the network addresses.  This means that the
+        host bits aren't considered at all in this method.  If you want
+        to compare host bits, you can easily enough do a
+        'HostA.ip < HostB.ip'
+
+        Args:
+            other: An IP object.
+
+        Returns:
+            If the IP versions of self and other are the same, returns:
+
+            -1 if self < other:
+              eg: IPv4('1.1.1.0/24') < IPv4('1.1.2.0/24')
+              IPv6('1080::200C:417A') < IPv6('1080::200B:417B')
+            0 if self == other
+              eg: IPv4('1.1.1.1/24') == IPv4('1.1.1.2/24')
+              IPv6('1080::200C:417A/96') == IPv6('1080::200C:417B/96')
+            1 if self > other
+              eg: IPv4('1.1.1.0/24') > IPv4('1.1.0.0/24')
+              IPv6('1080::1:200C:417A/112') >
+              IPv6('1080::0:200C:417A/112')
+
+            If the IP versions of self and other are different, returns:
+
+            -1 if self.version < other.version
+              eg: IPv4('10.0.0.1/24') < IPv6('::1/128')
+            1 if self.version > other.version
+              eg: IPv6('::1/128') > IPv4('255.255.255.0/24')
+
+        """
+        if self.version < other.version:
+            return -1
+        if self.version > other.version:
+            return 1
+        # self.version == other.version below here:
+        if self.network < other.network:
+            return -1
+        if self.network > other.network:
+            return 1
+        # self.network == other.network below here:
+        if self.netmask < other.netmask:
+            return -1
+        if self.netmask > other.netmask:
+            return 1
+        # self.network == other.network and self.netmask == other.netmask
+        return 0
+
+    def _get_networks_key(self):
+        """Network-only key function.
+
+        Returns an object that identifies this address' network and
+        netmask. This function is a suitable "key" argument for sorted()
+        and list.sort().
+
+        """
+        return (self.version, self.network, self.netmask)
+
+    prefixlen = property(
+        fget=lambda self: self._prefixlen,
+        fset=lambda self, prefixlen: self._set_prefix(prefixlen))
+
+    def __str__(self):
+        return  '%s/%s' % (self._string_from_ip_int(self.ip),
+                           str(self.prefixlen))
+
+    def __hash__(self):
+        return hash(self.ip ^ self.netmask)
+
+    def __contains__(self, other):
+        return self.network <= other.ip and self.broadcast >= other.broadcast
+
+    @property
+    def ip_ext(self):
+        """Dotted decimal or colon string version of the IP address."""
+        return self._string_from_ip_int(self.ip)
+
+    @property
+    def ip_ext_full(self):
+        """Canonical string version of the IP address."""
+        return self.ip_ext
+
+    @property
+    def broadcast(self):
+        """Integer representation of the broadcast address."""
+        return self.ip | self.hostmask
+
+    @property
+    def broadcast_ext(self):
+        """Dotted decimal or colon string version of the broadcast."""
+        return self._string_from_ip_int(self.broadcast)
+
+    @property
+    def hostmask(self):
+        """Integer representation of the hostmask."""
+        return self.netmask ^ self._ALL_ONES
+
+    @property
+    def hostmask_ext(self):
+        """Dotted decimal or colon string version of the hostmask."""
+        return self._string_from_ip_int(self.hostmask)
+
+    @property
+    def network(self):
+        """Integer representation of the network."""
+        return self.ip & self.netmask
+
+    @property
+    def network_ext(self):
+        """Dotted decimal or colon string version of the network."""
+        return self._string_from_ip_int(self.network)
+
+    @property
+    def netmask_ext(self):
+        """Dotted decimal or colon string version of the netmask."""
+        return self._string_from_ip_int(self.netmask)
+
+    @property
+    def numhosts(self):
+        """Number of hosts in the current subnet."""
+        return self.broadcast - self.network + 1
+
+    @property
+    def version(self):
+        raise NotImplementedError('BaseIP has no version')
+
+    def _ip_int_from_prefix(self, prefixlen=None):
+        """Turn the prefix length netmask into a int for comparison.
+
+        Args:
+            prefixlen: An integer, the prefix length.
+
+        Returns:
+            An integer.
+
+        """
+        if not prefixlen and prefixlen != 0:
+            prefixlen = self.prefixlen
+        return self._ALL_ONES ^ (self._ALL_ONES >> prefixlen)
+
+    def _prefix_from_ip_int(self, ip_int, mask=32):
+        """Return prefix length from the decimal netmask.
+
+        Args:
+            ip_int: An integer, the IP address.
+            mask: The netmask.  Defaults to 32.
+
+        Returns:
+            An integer, the prefix length.
+
+        """
+        while mask:
+            if ip_int & 1 == 1:
+                break
+            ip_int >>= 1
+            mask -= 1
+
+        return mask
+
+    def _ip_string_from_prefix(self, prefixlen=None):
+        """Turn a prefix length into a dotted decimal string.
+
+        Args:
+            prefixlen: An integer, the netmask prefix length.
+
+        Returns:
+            A string, the dotted decimal netmask string.
+
+        """
+        if not prefixlen:
+            prefixlen = self.prefixlen
+        return self._string_from_ip_int(self._ip_int_from_prefix(prefixlen))
+
+
+class IPv4(BaseIP):
+
+    """This class represents and manipulates 32-bit IPv4 addresses.
+
+    Attributes: [examples for IPv4('1.2.3.4/27')]
+        .ip: 16909060
+        .ip_ext: '1.2.3.4'
+        .ip_ext_full: '1.2.3.4'
+        .network: 16909056L
+        .network_ext: '1.2.3.0'
+        .hostmask: 31L (0x1F)
+        .hostmask_ext: '0.0.0.31'
+        .broadcast: 16909087L (0x102031F)
+        .broadcast_ext: '1.2.3.31'
+        .netmask: 4294967040L (0xFFFFFFE0)
+        .netmask_ext: '255.255.255.224'
+        .prefixlen: 27
+
+    """
+
+    # Equivalent to 255.255.255.255 or 32 bits of 1's.
+    _ALL_ONES = 0xffffffff
+
+    def __init__(self, ipaddr):
+        """Instantiate a new IPv4 object.
+
+        Args:
+            ipaddr: A string or integer representing the IP [& network].
+              '192.168.1.1/32'
+              '192.168.1.1/255.255.255.255'
+              '192.168.1.1/0.0.0.255'
+              '192.168.1.1'
+              are all functionally the same in IPv4. That is to say,
+              failing to provide a subnetmask will create an object with
+              a mask of /32. A netmask of '255.255.255.255' is assumed
+              to be /32 and '0.0.0.0' is assumed to be /0, even though
+              other netmasks can be expressed both as host- and
+              net-masks. (255.0.0.0 == 0.255.255.255)
+
+              Additionally, an integer can be passed, so
+              IPv4('192.168.1.1') == IPv4(3232235777).
+              or, more generally
+              IPv4(IPv4('192.168.1.1').ip) == IPv4('192.168.1.1')
+
+        Raises:
+            IPv4IpValidationError: If ipaddr isn't a valid IPv4 address.
+            IPv4NetmaskValidationError: If the netmask isn't valid for
+              an IPv4 address.
+
+        """
+        BaseIP.__init__(self)
+        self._version = 4
+
+        # Efficient constructor from integer.
+        if isinstance(ipaddr, int) or isinstance(ipaddr, long):
+            self.ip = ipaddr
+            self._prefixlen = 32
+            self.netmask = self._ALL_ONES
+            if ipaddr < 0 or ipaddr > self._ALL_ONES:
+                raise IPv4IpValidationError(ipaddr)
+            return
+
+        # Constructing from a packed address
+        if _compat_has_real_bytes:
+            if isinstance(ipaddr, bytes) and len(ipaddr) == 4:
+                self.ip = struct.unpack('!I', ipaddr)[0]
+                self._prefixlen = 32
+                self.netmask = self._ALL_ONES
+                return
+
+        # Assume input argument to be string or any object representation
+        # which converts into a formatted IP prefix string.
+        addr = str(ipaddr).split('/')
+
+        if len(addr) > 2:
+            raise IPv4IpValidationError(ipaddr)
+
+        if not self._is_valid_ip(addr[0]):
+            raise IPv4IpValidationError(addr[0])
+
+        self.ip = self._ip_int_from_string(addr[0])
+
+        if len(addr) == 2:
+            mask = addr[1].split('.')
+            if len(mask) == 4:
+                # We have dotted decimal netmask.
+                if not self._is_valid_netmask(addr[1]):
+                    raise IPv4NetmaskValidationError(addr[1])
+                if self._is_hostmask(addr[1]):
+                    self.netmask = (
+                        self._ip_int_from_string(addr[1]) ^ self._ALL_ONES)
+                else:
+                    self.netmask = self._ip_int_from_string(addr[1])
+                self._prefixlen = self._prefix_from_ip_int(self.netmask)
+            else:
+                # We have a netmask in prefix length form.
+                if not self._is_valid_netmask(addr[1]):
+                    raise IPv4NetmaskValidationError(addr[1])
+                self._prefixlen = int(addr[1])
+                self.netmask = self._ip_int_from_prefix(self._prefixlen)
+        else:
+            self._prefixlen = 32
+            self.netmask = self._ip_int_from_prefix(self._prefixlen)
+
+    def _set_prefix(self, prefixlen):
+        """Change the prefix length.
+
+        Args:
+            prefixlen: An integer, the new prefix length.
+
+        Raises:
+            IPv4NetmaskValidationError: If prefixlen is out of bounds.
+
+        """
+        if not 0 <= prefixlen <= 32:
+            raise IPv4NetmaskValidationError(prefixlen)
+        self._prefixlen = prefixlen
+        self.netmask = self._ip_int_from_prefix(self._prefixlen)
+
+    def subnet(self, prefixlen_diff=1):
+        """The subnets which join to make the current subnet.
+
+        In the case that self contains only one IP
+        (self._prefixlen == 32), return a list with just ourself.
+
+        Args:
+            prefixlen_diff: An integer, the amount the prefix length
+              should be increased by.  Given a /24 network and a
+              prefixlen_diff of 3, for example, 8 subnets of size /27
+              will be returned.  The default value of 1 splits the
+              current network into two halves.
+
+        Returns:
+            A list of IPv4 objects.
+
+        Raises:
+            PrefixlenDiffInvalidError: The prefixlen_diff is too small
+              or too large.
+
+        """
+        if self._prefixlen == 32:
+            return [self]
+
+        if prefixlen_diff < 0:
+            raise PrefixlenDiffInvalidError('prefix length diff must be > 0')
+        new_prefixlen = self.prefixlen + prefixlen_diff
+
+        if not self._is_valid_netmask(str(new_prefixlen)):
+            raise PrefixlenDiffInvalidError(
+                'prefix length diff %d is invalid for netblock %s' % (
+                    new_prefixlen, str(self)))
+
+        first = IPv4(
+            self._string_from_ip_int(self.network) + '/' +
+            str(self._prefixlen + prefixlen_diff))
+        subnets = [first]
+        current = first
+        while True:
+            broadcast = current.broadcast
+            if broadcast == self.broadcast:
+                break
+            current = IPv4(self._string_from_ip_int(broadcast + 1) + '/' +
+                           str(new_prefixlen))
+            subnets.append(current)
+
+        return subnets
+
+    def supernet(self, prefixlen_diff=1):
+        """The supernet containing the current network.
+
+        Args:
+            prefixlen_diff: An integer, the amount the prefix length of
+              the network should be decreased by.  For example, given a
+              /24 network and a prefixlen_diff of 3, a supernet with a
+              /21 netmask is returned.
+
+        Returns:
+            An IPv4 object.
+
+        Raises:
+            PrefixlenDiffInvalidError: If
+              self.prefixlen - prefixlen_diff < 0. I.e., you have a
+              negative prefix length.
+
+        """
+        if self.prefixlen == 0:
+            return self
+        if self.prefixlen - prefixlen_diff < 0:
+            raise PrefixlenDiffInvalidError(
+                'current prefixlen is %d, cannot have a prefixlen_diff of %d' %
+                (self.prefixlen, prefixlen_diff))
+        return IPv4(self.ip_ext + '/' + str(self.prefixlen - prefixlen_diff))
+
+    @property
+    def is_private(self):
+        """Test if this address is allocated for private networks.
+
+        Returns:
+            A boolean, True if the address is reserved per RFC 1918.
+
+        """
+        return (self in IPv4('10.0.0.0/8') or
+                self in IPv4('172.16.0.0/12') or
+                self in IPv4('192.168.0.0/16'))
+
+    @property
+    def is_multicast(self):
+        """Test if the address is reserved for multicast use.
+
+        Returns:
+            A boolean, True if the address is multicast.
+            See RFC 3171 for details.
+
+        """
+        return self in IPv4('224.0.0.0/4')
+
+    @property
+    def is_loopback(self):
+        """Test if the address is a loopback adddress.
+
+        Returns:
+            A boolean, True if the address is a loopback per RFC 3330.
+
+        """
+        return self in IPv4('127.0.0.0/8')
+
+    @property
+    def is_link_local(self):
+        """Test if the address is reserved for link-local.
+
+        Returns:
+            A boolean, True if the address is link-local per RFC 3927.
+
+        """
+        return self in IPv4('169.254.0.0/16')
+
+    @property
+    def version(self):
+        return self._version
+
+    @property
+    def packed(self):
+        """The binary representation of this address."""
+        return struct.pack('!I', self.ip)
+
+    def _is_hostmask(self, ip_str):
+        """Test if the IP string is a hostmask (rather than a netmask).
+
+        Args:
+            ip_str: A string, the potential hostmask.
+
+        Returns:
+            A boolean, True if the IP string is a hostmask.
+
+        """
+        parts = [int(x) for x in ip_str.split('.')]
+        if parts[0] < parts[-1]:
+            return True
+        return False
+
+    def _ip_int_from_string(self, ip_str):
+        """Turn the given IP string into an integer for comparison.
+
+        Args:
+            ip_str: A string, the IP address.
+
+        Returns:
+            The IP address as an integer.
+
+        """
+        packed_ip = 0
+        for oc in ip_str.split('.'):
+            packed_ip = (packed_ip << 8) | int(oc)
+        return packed_ip
+
+    def _string_from_ip_int(self, ip_int):
+        """Turns a 32-bit integer into dotted decimal notation.
+
+        Args:
+            ip_int: An integer, the IP address.
+
+        Returns:
+            The IP address as a string in dotted decimal notation.
+
+        """
+        octets = []
+        for _ in xrange(4):
+            octets.insert(0, str(ip_int & 0xFF))
+            ip_int >>= 8
+        return '.'.join(octets)
+
+    def _is_valid_ip(self, ip_str):
+        """Validate the dotted decimal notation IP/netmask string.
+
+        Args:
+            ip_str: A string, the IP address.
+
+        Returns:
+            A boolean, True if the string is a valid dotted decimal IP
+            string.
+
+        """
+        octets = ip_str.split('.')
+        if len(octets) == 1:
+            # We have an integer rather than a dotted decimal IP.
+            try:
+                return int(ip_str) >= 0 and int(ip_str) <= self._ALL_ONES
+            except ValueError:
+                return False
+
+        if len(octets) != 4:
+            return False
+
+        for octet in octets:
+            try:
+                if not 0 <= int(octet) <= 255:
+                    return False
+            except ValueError:
+                return False
+        return True
+
+    def _is_valid_netmask(self, netmask):
+        """Verify that the netmask is valid.
+
+        Args:
+            netmask: A string, either a prefix or dotted decimal
+              netmask.
+
+        Returns:
+            A boolean, True if the prefix represents a valid IPv4
+            netmask.
+
+        """
+        if len(netmask.split('.')) == 4:
+            return self._is_valid_ip(netmask)
+        try:
+            netmask = int(netmask)
+        except ValueError:
+            return False
+        return 0 <= netmask <= 32
+
+
+class IPv6(BaseIP):
+
+    """This class respresents and manipulates 128-bit IPv6 addresses.
+
+    Attributes: [examples for IPv6('2001:658:22A:CAFE:200::1/64')]
+        .ip: 42540616829182469433547762482097946625L
+        .ip_ext: '2001:658:22a:cafe:200::1'
+        .ip_ext_full: '2001:0658:022a:cafe:0200:0000:0000:0001'
+        .network: 42540616829182469433403647294022090752L
+        .network_ext: '2001:658:22a:cafe::'
+        .hostmask: 18446744073709551615L
+        .hostmask_ext: '::ffff:ffff:ffff:ffff'
+        .broadcast: 42540616829182469451850391367731642367L
+        .broadcast_ext: '2001:658:22a:cafe:ffff:ffff:ffff:ffff'
+        .netmask: 340282366920938463444927863358058659840L
+        .netmask_ext: 64
+        .prefixlen: 64
+
+    """
+
+    _ALL_ONES = (2**128) - 1
+
+    def __init__(self, ipaddr):
+        """Instantiate a new IPv6 object.
+
+        Args:
+            ipaddr: A string or integer representing the IP or the IP
+              and prefix/netmask.
+              '2001:4860::/128'
+              '2001:4860:0000:0000:0000:0000:0000:0000/128'
+              '2001:4860::'
+              are all functionally the same in IPv6.  That is to say,
+              failing to provide a subnetmask will create an object with
+              a mask of /128.
+
+              Additionally, an integer can be passed, so
+              IPv6('2001:4860::') ==
+              IPv6(42541956101370907050197289607612071936L).
+              or, more generally
+              IPv6(IPv6('2001:4860::').ip) == IPv6('2001:4860::')
+
+        Raises:
+            IPv6IpValidationError: If ipaddr isn't a valid IPv6 address.
+            IPv6NetmaskValidationError: If the netmask isn't valid for
+              an IPv6 address.
+
+        """
+        BaseIP.__init__(self)
+        self._version = 6
+
+        # Efficient constructor from integer.
+        if isinstance(ipaddr, long) or isinstance(ipaddr, int):
+            self.ip = ipaddr
+            self._prefixlen = 128
+            self.netmask = self._ALL_ONES
+            if ipaddr < 0 or ipaddr > self._ALL_ONES:
+                raise IPv6IpValidationError(ipaddr)
+            return
+
+        # Constructing from a packed address
+        if _compat_has_real_bytes:
+            if isinstance(ipaddr, bytes) and len(ipaddr) == 16:
+                tmp = struct.unpack('!QQ', ipaddr)
+                self.ip = (tmp[0] << 64) | tmp[1]
+                self._prefixlen = 128
+                self.netmask = self._ALL_ONES
+                return
+
+        # Assume input argument to be string or any object representation
+        # which converts into a formatted IP prefix string.
+        addr_str = str(ipaddr)
+        if not addr_str:
+            raise IPv6IpValidationError('')
+        addr = addr_str.split('/')
+        if len(addr) > 1:
+            if self._is_valid_netmask(addr[1]):
+                self._prefixlen = int(addr[1])
+            else:
+                raise IPv6NetmaskValidationError(addr[1])
+        else:
+            self._prefixlen = 128
+
+        self.netmask = self._ip_int_from_prefix(self._prefixlen)
+
+        if not self._is_valid_ip(addr[0]):
+            raise IPv6IpValidationError(addr[0])
+
+        self.ip = self._ip_int_from_string(addr[0])
+
+    @property
+    def ip_ext_full(self):
+        """Returns the expanded version of the IPv6 string."""
+        return self._explode_shorthand_ip_string(self.ip_ext)
+
+    def _set_prefix(self, prefixlen):
+        """Change the prefix length.
+
+        Args:
+            prefixlen: An integer, the new prefix length.
+
+        Raises:
+            IPv6NetmaskValidationError: If prefixlen is out of bounds.
+
+        """
+        if not 0 <= prefixlen <= 128:
+            raise IPv6NetmaskValidationError(prefixlen)
+        self._prefixlen = prefixlen
+        self.netmask = self._ip_int_from_prefix(self.prefixlen)
+
+    def subnet(self, prefixlen_diff=1):
+        """The subnets which join to make the current subnet.
+
+        In the case that self contains only one IP
+        (self._prefixlen == 128), return a list with just ourself.
+
+        Args:
+            prefixlen_diff: An integer, the amount the prefix length
+              should be increased by.
+
+        Returns:
+            A list of IPv6 objects.
+
+        Raises:
+            PrefixlenDiffInvalidError: The prefixlen_diff is too small
+              or too large.
+
+        """
+        # Preserve original functionality (return [self] if
+        # self.prefixlen == 128).
+        if self.prefixlen == 128:
+            return [self]
+
+        if prefixlen_diff < 0:
+            raise PrefixlenDiffInvalidError('Prefix length diff must be > 0')
+        new_prefixlen = self.prefixlen + prefixlen_diff
+        if not self._is_valid_netmask(str(new_prefixlen)):
+            raise PrefixlenDiffInvalidError(
+                'Prefix length diff %d is invalid for netblock %s' % (
+                new_prefixlen, str(self)))
+        first = IPv6(
+            self._string_from_ip_int(self.network) + '/' +
+            str(self._prefixlen + prefixlen_diff))
+        subnets = [first]
+        current = first
+        while True:
+            broadcast = current.broadcast
+            if current.broadcast == self.broadcast:
+                break
+            current = IPv6(self._string_from_ip_int(broadcast + 1) + '/' +
+                           str(new_prefixlen))
+            subnets.append(current)
+
+        return subnets
+
+    def supernet(self, prefixlen_diff=1):
+        """The supernet containing the current network.
+
+        Args:
+            prefixlen_diff: An integer, the amount the prefix length of the
+              network should be decreased by.  For example, given a /96
+              network and a prefixlen_diff of 3, a supernet with a /93
+              netmask is returned.
+
+        Returns:
+            An IPv6 object.
+
+        Raises:
+            PrefixlenDiffInvalidError: If
+              self._prefixlen - prefixlen_diff < 0. I.e., you have a
+              negative prefix length.
+
+        """
+        if self.prefixlen == 0:
+            return self
+        if self.prefixlen - prefixlen_diff < 0:
+            raise PrefixlenDiffInvalidError(
+                'current prefixlen is %d, cannot have a prefixlen_diff of %d' %
+                (self.prefixlen, prefixlen_diff))
+        return IPv6(self.ip_ext + '/' + str(self.prefixlen - prefixlen_diff))
+
+    @property
+    def is_multicast(self):
+        """Test if the address is reserved for multicast use.
+
+        Returns:
+            A boolean, True if the address is a multicast address.
+            See RFC 2373 2.7 for details.
+
+        """
+        return self in IPv6('ff00::/8')
+
+    @property
+    def is_unspecified(self):
+        """Test if the address is unspecified.
+
+        Returns:
+            A boolean, True if this is the unspecified address as defined in
+            RFC 2373 2.5.2.
+
+        """
+        return self == IPv6('::')
+
+    @property
+    def is_loopback(self):
+        """Test if the address is a loopback adddress.
+
+        Returns:
+            A boolean, True if the address is a loopback address as defined in
+            RFC 2373 2.5.3.
+
+        """
+        return self == IPv6('::1')
+
+    @property
+    def is_link_local(self):
+        """Test if the address is reserved for link-local.
+
+        Returns:
+            A boolean, True if the address is reserved per RFC 4291.
+
+        """
+        return self in IPv6('fe80::/10')
+
+    @property
+    def is_site_local(self):
+        """Test if the address is reserved for site-local.
+
+        Note that the site-local address space has been deprecated by RFC 3879.
+        Use is_private to test if this address is in the space of unique local
+        addresses as defined by RFC 4193.
+
+        Returns:
+            A boolean, True if the address is reserved per RFC 3513 2.5.6.
+
+        """
+        return self in IPv6('fec0::/10')
+
+    @property
+    def is_private(self):
+        """Test if this address is allocated for private networks.
+
+        Returns:
+            A boolean, True if the address is reserved per RFC 4193.
+
+        """
+        return self in IPv6('fc00::/7')
+
+    @property
+    def version(self):
+        return self._version
+
+    @property
+    def packed(self):
+        """The binary representation of this address."""
+        return struct.pack('!QQ', self.ip >> 64, self.ip & (2**64 - 1))
+
+    def _is_shorthand_ip(self, ip_str=None):
+        """Determine if the address is shortened.
+
+        Args:
+            ip_str: A string, the IPv6 address.
+
+        Returns:
+            A boolean, True if the address is shortened.
+
+        """
+        if ip_str.count('::') == 1:
+            return True
+        return False
+
+    def _explode_shorthand_ip_string(self, ip_str):
+        """Expand a shortened IPv6 address.
+
+        Args:
+            ip_str: A string, the IPv6 address.
+
+        Returns:
+            A string, the expanded IPv6 address.
+
+        """
+        if self._is_shorthand_ip(ip_str):
+            new_ip = []
+            hextet = ip_str.split('::')
+            sep = len(hextet[0].split(':')) + len(hextet[1].split(':'))
+            new_ip = hextet[0].split(':')
+
+            for _ in xrange(8 - sep):
+                new_ip.append('0000')
+            new_ip += hextet[1].split(':')
+
+            # Now need to make sure every hextet is 4 lower case characters.
+            # If a hextet is < 4 characters, we've got missing leading 0's.
+            ret_ip = []
+            for hextet in new_ip:
+                ret_ip.append(('0' * (4 - len(hextet)) + hextet).lower())
+            return ':'.join(ret_ip)
+        # We've already got a longhand ip_str.
+        return ip_str
+
+    def _is_valid_ip(self, ip_str=None):
+        """Ensure we have a valid IPv6 address.
+
+        Probably not as exhaustive as it should be.
+
+        Args:
+            ip_str: A string, the IPv6 address.
+
+        Returns:
+            A boolean, True if this is a valid IPv6 address.
+
+        """
+        if not ip_str:
+            ip_str = self.ip_ext
+
+        # We need to have at least one ':'.
+        if ':' not in ip_str:
+            return False
+
+        # We can only have one '::' shortener.
+        if ip_str.count('::') > 1:
+            return False
+
+        # '::' should be encompassed by start, digits or end.
+        if ':::' in ip_str:
+            return False
+
+        # A single colon can neither start nor end an address.
+        if ((ip_str.startswith(':') and not ip_str.startswith('::')) or
+                (ip_str.endswith(':') and not ip_str.endswith('::'))):
+            return False
+
+        # If we have no concatenation, we need to have 8 fields with 7 ':'.
+        if '::' not in ip_str and ip_str.count(':') != 7:
+            # We might have an IPv4 mapped address.
+            if ip_str.count('.') != 3:
+                return False
+
+        ip_str = self._explode_shorthand_ip_string(ip_str)
+
+        # Now that we have that all squared away, let's check that each of the
+        # hextets are between 0x0 and 0xFFFF.
+        for hextet in ip_str.split(':'):
+            if hextet.count('.') == 3:
+                # If we have an IPv4 mapped address, the IPv4 portion has to be
+                # at the end of the IPv6 portion.
+                if not ip_str.split(':')[-1] == hextet:
+                    return False
+                try:
+                    IPv4(hextet)
+                except IPv4IpValidationError:
+                    return False
+            elif int(hextet, 16) < 0x0 or int(hextet, 16) > 0xFFFF:
+                return False
+        return True
+
+    def _is_valid_netmask(self, prefixlen):
+        """Verify that the netmask/prefixlen is valid.
+
+        Args:
+            prefixlen: A string, the netmask in prefix length format.
+
+        Returns:
+            A boolean, True if the prefix represents a valid IPv6
+            netmask.
+
+        """
+        try:
+            prefixlen = int(prefixlen)
+        except ValueError:
+            return False
+        return 0 <= prefixlen <= 128
+
+    def _ip_int_from_string(self, ip_str=None):
+        """Turn an IPv6 address into an integer.
+
+        Args:
+            ip_str: A string, the IPv6 address.
+
+        Returns:
+            A long, the IPv6 address.
+
+        """
+        if not ip_str:
+            ip_str = self.ip_ext
+
+        ip_int = 0
+
+        fields = self._explode_shorthand_ip_string(ip_str).split(':')
+
+        # Do we have an IPv4 mapped (::ffff:a.b.c.d) or compact (::a.b.c.d)
+        # address?
+        if fields[-1].count('.') == 3:
+            ipv4_string = fields.pop()
+            ipv4_int = IPv4(ipv4_string).ip
+            octets = []
+            for _ in xrange(2):
+                octets.append(hex(ipv4_int & 0xFFFF).lstrip('0x').rstrip('L'))
+                ipv4_int >>= 16
+            fields.extend(reversed(octets))
+
+        for field in fields:
+            ip_int = (ip_int << 16) + int(field, 16)
+
+        return ip_int
+
+    def _compress_hextets(self, hextets):
+        """Compresses a list of hextets.
+
+        Compresses a list of strings, replacing the longest continuous
+        sequence of "0" in the list with "" and adding empty strings at
+        the beginning or at the end of the string such that subsequently
+        calling ":".join(hextets) will produce the compressed version of
+        the IPv6 address.
+
+        Args:
+            hextets: A list of strings, the hextets to compress.
+
+        Returns:
+            A list of strings.
+
+        """
+        best_doublecolon_start = -1
+        best_doublecolon_len = 0
+        doublecolon_start = -1
+        doublecolon_len = 0
+        for index in range(len(hextets)):
+            if hextets[index] == '0':
+                doublecolon_len += 1
+                if doublecolon_start == -1:
+                    # Start of a sequence of zeros.
+                    doublecolon_start = index
+                if doublecolon_len > best_doublecolon_len:
+                    # This is the longest sequence of zeros so far.
+                    best_doublecolon_len = doublecolon_len
+                    best_doublecolon_start = doublecolon_start
+            else:
+                doublecolon_len = 0
+                doublecolon_start = -1
+
+        if best_doublecolon_len > 1:
+            best_doublecolon_end = (best_doublecolon_start +
+                                    best_doublecolon_len)
+            # For zeros at the end of the address.
+            if best_doublecolon_end == len(hextets):
+                hextets += ['']
+            hextets[best_doublecolon_start:best_doublecolon_end] = ['']
+            # For zeros at the beginning of the address.
+            if best_doublecolon_start == 0:
+                hextets = [''] + hextets
+
+        return hextets
+
+    def _string_from_ip_int(self, ip_int=None):
+        """Turns a 128-bit integer into hexadecimal notation.
+
+        Args:
+            ip_int: An integer, the IP address.
+
+        Returns:
+            A string, the hexadecimal representation of the address.
+
+        Raises:
+            ValueError: The address is bigger than 128 bits of all ones.
+
+        """
+        if not ip_int and ip_int != 0:
+            ip_int = self.ip
+
+        if ip_int > self._ALL_ONES:
+            raise ValueError('IPv6 address is too large')
+
+        hex_str = '%032x' % ip_int
+        hextets = []
+        for x in range(0, 32, 4):
+            hextets.append('%x' % int(hex_str[x:x+4], 16))
+
+        hextets = self._compress_hextets(hextets)
+        return ':'.join(hextets)
+
+    @property
+    def netmask_ext(self):
+        """IPv6 extended netmask.
+
+        We don't deal with netmasks in IPv6 like we do in IPv4.  This is
+        here strictly for IPv4 compatibility.  We simply return the
+        prefix length.
+
+        Returns:
+            An integer.
+
+        """
+        return self.prefixlen
diff --git a/Lib/test/test_ipaddr.py b/Lib/test/test_ipaddr.py
new file mode 100755
index 0000000..16ebb86
--- /dev/null
+++ b/Lib/test/test_ipaddr.py
@@ -0,0 +1,567 @@
+# Copyright 2007 Google Inc.
+#  Licensed to PSF under a Contributor Agreement.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# See also:  http://code.google.com/p/ipaddr-py/
+
+"""Unittest for ipaddr module."""
+
+
+import unittest
+
+import ipaddr
+
+# Compatibility function to cast str to bytes objects
+if ipaddr._compat_has_real_bytes:
+    _cb = lambda bytestr: bytes(bytestr, 'charmap')
+else:
+    _cb = str
+
+class IpaddrUnitTest(unittest.TestCase):
+
+    def setUp(self):
+        self.ipv4 = ipaddr.IPv4('1.2.3.4/24')
+        self.ipv4_hostmask = ipaddr.IPv4('10.0.0.1/0.255.255.255')
+        self.ipv6 = ipaddr.IPv6('2001:658:22a:cafe:200:0:0:1/64')
+
+    def testRepr(self):
+        self.assertEqual("IPv4('1.2.3.4/32')", repr(ipaddr.IPv4('1.2.3.4')))
+        self.assertEqual("IPv6('::1/128')", repr(ipaddr.IPv6('::1')))
+
+    def testInvalidStrings(self):
+        self.assertRaises(ValueError, ipaddr.IP, '')
+        self.assertRaises(ValueError, ipaddr.IP, 'www.google.com')
+        self.assertRaises(ValueError, ipaddr.IP, '1.2.3')
+        self.assertRaises(ValueError, ipaddr.IP, '1.2.3.4.5')
+        self.assertRaises(ValueError, ipaddr.IP, '301.2.2.2')
+        self.assertRaises(ValueError, ipaddr.IP, '1:2:3:4:5:6:7')
+        self.assertRaises(ValueError, ipaddr.IP, '1:2:3:4:5:6:7:')
+        self.assertRaises(ValueError, ipaddr.IP, ':2:3:4:5:6:7:8')
+        self.assertRaises(ValueError, ipaddr.IP, '1:2:3:4:5:6:7:8:9')
+        self.assertRaises(ValueError, ipaddr.IP, '1:2:3:4:5:6:7:8:')
+        self.assertRaises(ValueError, ipaddr.IP, '1::3:4:5:6::8')
+        self.assertRaises(ValueError, ipaddr.IP, 'a:')
+        self.assertRaises(ValueError, ipaddr.IP, ':')
+        self.assertRaises(ValueError, ipaddr.IP, ':::')
+        self.assertRaises(ValueError, ipaddr.IP, '::a:')
+        self.assertRaises(ValueError, ipaddr.IP, '1ffff::')
+        self.assertRaises(ValueError, ipaddr.IP, '0xa::')
+        self.assertRaises(ValueError, ipaddr.IP, '1:2:3:4:5:6:1a.2.3.4')
+        self.assertRaises(ValueError, ipaddr.IP, '1:2:3:4:5:1.2.3.4:8')
+        self.assertRaises(ipaddr.IPv4IpValidationError, ipaddr.IPv4, '')
+        self.assertRaises(ipaddr.IPv4IpValidationError, ipaddr.IPv4,
+                          'google.com')
+        self.assertRaises(ipaddr.IPv4IpValidationError, ipaddr.IPv4,
+                          '::1.2.3.4')
+        self.assertRaises(ipaddr.IPv6IpValidationError, ipaddr.IPv6, '')
+        self.assertRaises(ipaddr.IPv6IpValidationError, ipaddr.IPv6,
+                          'google.com')
+        self.assertRaises(ipaddr.IPv6IpValidationError, ipaddr.IPv6,
+                          '1.2.3.4')
+
+    def testGetNetwork(self):
+        self.assertEqual(self.ipv4.network, 16909056)
+        self.assertEqual(self.ipv4.network_ext, '1.2.3.0')
+        self.assertEqual(self.ipv4_hostmask.network_ext, '10.0.0.0')
+
+        self.assertEqual(self.ipv6.network,
+                         42540616829182469433403647294022090752)
+        self.assertEqual(self.ipv6.network_ext,
+                         '2001:658:22a:cafe::')
+        self.assertEqual(self.ipv6.hostmask_ext,
+                         '::ffff:ffff:ffff:ffff')
+
+    def testIpFromInt(self):
+        self.assertEqual(self.ipv4.ip, ipaddr.IPv4(16909060).ip)
+        self.assertRaises(ipaddr.IPv4IpValidationError,
+                          ipaddr.IPv4, 2**32)
+        self.assertRaises(ipaddr.IPv4IpValidationError,
+                          ipaddr.IPv4, -1)
+
+        self.assertEqual(self.ipv6.ip,
+                         ipaddr.IPv6(42540616829182469433547762482097946625).ip)
+        self.assertRaises(ipaddr.IPv6IpValidationError,
+                          ipaddr.IPv6, 2**128)
+        self.assertRaises(ipaddr.IPv6IpValidationError,
+                          ipaddr.IPv6, -1)
+
+        self.assertEqual(ipaddr.IP(self.ipv4.ip).version, 4)
+        self.assertEqual(ipaddr.IP(self.ipv6.ip).version, 6)
+
+    if ipaddr._compat_has_real_bytes: # on python3+
+        def testIpFromPacked(self):
+            ip = ipaddr.IP
+
+            self.assertEqual(self.ipv4.ip,
+                             ip(_cb('\x01\x02\x03\x04')).ip)
+            self.assertEqual(ip('255.254.253.252'),
+                             ip(_cb('\xff\xfe\xfd\xfc')))
+            self.assertRaises(ValueError, ipaddr.IP, _cb('\x00' * 3))
+            self.assertRaises(ValueError, ipaddr.IP, _cb('\x00' * 5))
+            self.assertEqual(self.ipv6.ip,
+                             ip(_cb('\x20\x01\x06\x58\x02\x2a\xca\xfe'
+                               '\x02\x00\x00\x00\x00\x00\x00\x01')).ip)
+            self.assertEqual(ip('ffff:2:3:4:ffff::'),
+                             ip(_cb('\xff\xff\x00\x02\x00\x03\x00\x04' +
+                                   '\xff\xff' + '\x00' * 6)))
+            self.assertEqual(ip('::'),
+                             ip(_cb('\x00' * 16)))
+            self.assertRaises(ValueError, ip, _cb('\x00' * 15))
+            self.assertRaises(ValueError, ip, _cb('\x00' * 17))
+
+    def testGetIp(self):
+        self.assertEqual(self.ipv4.ip, 16909060)
+        self.assertEqual(self.ipv4.ip_ext, '1.2.3.4')
+        self.assertEqual(self.ipv4.ip_ext_full, '1.2.3.4')
+        self.assertEqual(self.ipv4_hostmask.ip_ext, '10.0.0.1')
+
+        self.assertEqual(self.ipv6.ip, 42540616829182469433547762482097946625)
+        self.assertEqual(self.ipv6.ip_ext,
+                         '2001:658:22a:cafe:200::1')
+        self.assertEqual(self.ipv6.ip_ext_full,
+                         '2001:0658:022a:cafe:0200:0000:0000:0001')
+
+    def testGetNetmask(self):
+        self.assertEqual(self.ipv4.netmask, 4294967040)
+        self.assertEqual(self.ipv4.netmask_ext, '255.255.255.0')
+        self.assertEqual(self.ipv4_hostmask.netmask_ext, '255.0.0.0')
+        self.assertEqual(self.ipv6.netmask,
+                         340282366920938463444927863358058659840)
+        self.assertEqual(self.ipv6.netmask_ext, 64)
+
+    def testZeroNetmask(self):
+        ipv4_zero_netmask = ipaddr.IPv4('1.2.3.4/0')
+        self.assertEqual(ipv4_zero_netmask.netmask, 0)
+        self.assert_(ipv4_zero_netmask._is_valid_netmask(str(0)))
+
+        ipv6_zero_netmask = ipaddr.IPv6('::1/0')
+        self.assertEqual(ipv6_zero_netmask.netmask, 0)
+        self.assert_(ipv6_zero_netmask._is_valid_netmask(str(0)))
+
+    def testGetBroadcast(self):
+        self.assertEqual(self.ipv4.broadcast, 16909311)
+        self.assertEqual(self.ipv4.broadcast_ext, '1.2.3.255')
+
+        self.assertEqual(self.ipv6.broadcast,
+                         42540616829182469451850391367731642367)
+        self.assertEqual(self.ipv6.broadcast_ext,
+                         '2001:658:22a:cafe:ffff:ffff:ffff:ffff')
+
+    def testGetPrefixlen(self):
+        self.assertEqual(self.ipv4.prefixlen, 24)
+
+        self.assertEqual(self.ipv6.prefixlen, 64)
+
+    def testGetSupernet(self):
+        self.assertEqual(self.ipv4.supernet().prefixlen, 23)
+        self.assertEqual(self.ipv4.supernet().network_ext, '1.2.2.0')
+        self.assertEqual(ipaddr.IPv4('0.0.0.0/0').supernet(),
+                         ipaddr.IPv4('0.0.0.0/0'))
+
+        self.assertEqual(self.ipv6.supernet().prefixlen, 63)
+        self.assertEqual(self.ipv6.supernet().network_ext,
+                         '2001:658:22a:cafe::')
+        self.assertEqual(ipaddr.IPv6('::0/0').supernet(), ipaddr.IPv6('::0/0'))
+
+    def testGetSupernet3(self):
+        self.assertEqual(self.ipv4.supernet(3).prefixlen, 21)
+        self.assertEqual(self.ipv4.supernet(3).network_ext, '1.2.0.0')
+
+        self.assertEqual(self.ipv6.supernet(3).prefixlen, 61)
+        self.assertEqual(self.ipv6.supernet(3).network_ext,
+                         '2001:658:22a:caf8::')
+
+    def testGetSubnet(self):
+        self.assertEqual(self.ipv4.subnet()[0].prefixlen, 25)
+        self.assertEqual(self.ipv4.subnet()[0].network_ext, '1.2.3.0')
+        self.assertEqual(self.ipv4.subnet()[1].network_ext, '1.2.3.128')
+
+        self.assertEqual(self.ipv6.subnet()[0].prefixlen, 65)
+
+    def testGetSubnetForSingle32(self):
+        ip = ipaddr.IPv4('1.2.3.4/32')
+        subnets1 = [str(x) for x in ip.subnet()]
+        subnets2 = [str(x) for x in ip.subnet(2)]
+        self.assertEqual(subnets1, ['1.2.3.4/32'])
+        self.assertEqual(subnets1, subnets2)
+
+    def testGetSubnetForSingle128(self):
+        ip = ipaddr.IPv6('::1/128')
+        subnets1 = [str(x) for x in ip.subnet()]
+        subnets2 = [str(x) for x in ip.subnet(2)]
+        self.assertEqual(subnets1, ['::1/128'])
+        self.assertEqual(subnets1, subnets2)
+
+    def testSubnet2(self):
+        ips = [str(x) for x in self.ipv4.subnet(2)]
+        self.assertEqual(
+            ips,
+            ['1.2.3.0/26', '1.2.3.64/26', '1.2.3.128/26', '1.2.3.192/26'])
+
+        ipsv6 = [str(x) for x in self.ipv6.subnet(2)]
+        self.assertEqual(
+            ipsv6,
+            ['2001:658:22a:cafe::/66',
+             '2001:658:22a:cafe:4000::/66',
+             '2001:658:22a:cafe:8000::/66',
+             '2001:658:22a:cafe:c000::/66'])
+
+    def testSubnetFailsForLargeCidrDiff(self):
+        self.assertRaises(ipaddr.PrefixlenDiffInvalidError, self.ipv4.subnet, 9)
+        self.assertRaises(ipaddr.PrefixlenDiffInvalidError, self.ipv6.subnet,
+                          65)
+
+    def testSupernetFailsForLargeCidrDiff(self):
+        self.assertRaises(ipaddr.PrefixlenDiffInvalidError, self.ipv4.supernet,
+                          25)
+        self.assertRaises(ipaddr.PrefixlenDiffInvalidError, self.ipv6.supernet,
+                          65)
+
+    def testSubnetFailsForNegativeCidrDiff(self):
+        self.assertRaises(ipaddr.PrefixlenDiffInvalidError, self.ipv4.subnet,
+                          -1)
+        self.assertRaises(ipaddr.PrefixlenDiffInvalidError, self.ipv6.subnet,
+                          -1)
+
+    def testGetNumHosts(self):
+        self.assertEqual(self.ipv4.numhosts, 256)
+        self.assertEqual(self.ipv4.subnet()[0].numhosts, 128)
+        self.assertEqual(self.ipv4.supernet().numhosts, 512)
+
+        self.assertEqual(self.ipv6.numhosts, 18446744073709551616)
+        self.assertEqual(self.ipv6.subnet()[0].numhosts, 9223372036854775808)
+        self.assertEqual(self.ipv6.supernet().numhosts, 36893488147419103232)
+
+    def testContains(self):
+        self.assertTrue(ipaddr.IPv4('1.2.3.128/25') in self.ipv4)
+        self.assertFalse(ipaddr.IPv4('1.2.4.1/24') in self.ipv4)
+        self.assertFalse(self.ipv4 in self.ipv6)
+        self.assertFalse(self.ipv6 in self.ipv4)
+        self.assertTrue(self.ipv4 in self.ipv4)
+        self.assertTrue(self.ipv6 in self.ipv6)
+
+    def testBadAddress(self):
+        self.assertRaises(ipaddr.IPv4IpValidationError, ipaddr.IPv4, 'poop')
+        self.assertRaises(ipaddr.IPv4IpValidationError,
+                          ipaddr.IPv4, '1.2.3.256')
+
+        self.assertRaises(ipaddr.IPv6IpValidationError, ipaddr.IPv6, 'poopv6')
+        self.assertRaises(ipaddr.IPv4IpValidationError,
+                          ipaddr.IPv4, '1.2.3.4/32/24')
+
+    def testBadNetMask(self):
+        self.assertRaises(ipaddr.IPv4NetmaskValidationError,
+                          ipaddr.IPv4, '1.2.3.4/')
+        self.assertRaises(ipaddr.IPv4NetmaskValidationError,
+                          ipaddr.IPv4, '1.2.3.4/33')
+        self.assertRaises(ipaddr.IPv4NetmaskValidationError,
+                          ipaddr.IPv4, '1.2.3.4/254.254.255.256')
+
+        self.assertRaises(ipaddr.IPv6NetmaskValidationError,
+                          ipaddr.IPv6, '::1/')
+        self.assertRaises(ipaddr.IPv6NetmaskValidationError,
+                          ipaddr.IPv6, '::1/129')
+
+    def testNth(self):
+        self.assertEqual(self.ipv4[5], '1.2.3.5')
+        self.assertRaises(IndexError, self.ipv4.__getitem__, 256)
+
+        self.assertEqual(self.ipv6[5],
+                         '2001:658:22a:cafe::5')
+
+    def testEquals(self):
+        self.assertTrue(self.ipv4 == ipaddr.IPv4('1.2.3.4/24'))
+        self.assertFalse(self.ipv4 == ipaddr.IPv4('1.2.3.4/23'))
+        self.assertFalse(self.ipv4 == ipaddr.IPv4('1.2.3.5/24'))
+        self.assertFalse(self.ipv4 == ipaddr.IPv6('::1.2.3.4/24'))
+        self.assertFalse(self.ipv4 == '')
+        self.assertFalse(self.ipv4 == [])
+        self.assertFalse(self.ipv4 == 2)
+
+        self.assertTrue(self.ipv6 ==
+            ipaddr.IPv6('2001:658:22a:cafe:200::1/64'))
+        self.assertFalse(self.ipv6 ==
+            ipaddr.IPv6('2001:658:22a:cafe:200::1/63'))
+        self.assertFalse(self.ipv6 ==
+            ipaddr.IPv6('2001:658:22a:cafe:200::2/64'))
+        self.assertFalse(self.ipv6 == ipaddr.IPv4('1.2.3.4/23'))
+        self.assertFalse(self.ipv6 == '')
+        self.assertFalse(self.ipv6 == [])
+        self.assertFalse(self.ipv6 == 2)
+
+    def testNotEquals(self):
+        self.assertFalse(self.ipv4 != ipaddr.IPv4('1.2.3.4/24'))
+        self.assertTrue(self.ipv4 != ipaddr.IPv4('1.2.3.4/23'))
+        self.assertTrue(self.ipv4 != ipaddr.IPv4('1.2.3.5/24'))
+        self.assertTrue(self.ipv4 != ipaddr.IPv6('::1.2.3.4/24'))
+        self.assertTrue(self.ipv4 != '')
+        self.assertTrue(self.ipv4 != [])
+        self.assertTrue(self.ipv4 != 2)
+
+        self.assertFalse(self.ipv6 !=
+            ipaddr.IPv6('2001:658:22a:cafe:200::1/64'))
+        self.assertTrue(self.ipv6 !=
+            ipaddr.IPv6('2001:658:22a:cafe:200::1/63'))
+        self.assertTrue(self.ipv6 !=
+            ipaddr.IPv6('2001:658:22a:cafe:200::2/64'))
+        self.assertTrue(self.ipv6 != ipaddr.IPv4('1.2.3.4/23'))
+        self.assertTrue(self.ipv6 != '')
+        self.assertTrue(self.ipv6 != [])
+        self.assertTrue(self.ipv6 != 2)
+
+    def testSlash32Constructor(self):
+        self.assertEquals(str(ipaddr.IPv4('1.2.3.4/255.255.255.255')),
+                          '1.2.3.4/32')
+
+    def testSlash128Constructor(self):
+        self.assertEquals(str(ipaddr.IPv6('::1/128')),
+                                  '::1/128')
+
+    def testSlash0Constructor(self):
+        self.assertEquals(str(ipaddr.IPv4('1.2.3.4/0.0.0.0')), '1.2.3.4/0')
+
+    def testCollapsing(self):
+        ip1 = ipaddr.IPv4('1.1.0.0/24')
+        ip2 = ipaddr.IPv4('1.1.1.0/24')
+        ip3 = ipaddr.IPv4('1.1.2.0/24')
+        ip4 = ipaddr.IPv4('1.1.3.0/24')
+        ip5 = ipaddr.IPv4('1.1.4.0/24')
+        # stored in no particular order b/c we want CollapseAddr to call [].sort
+        ip6 = ipaddr.IPv4('1.1.0.0/22')
+        # check that addreses are subsumed properlly.
+        collapsed = ipaddr.collapse_address_list([ip1, ip2, ip3, ip4, ip5, ip6])
+        self.assertEqual(collapsed, [ipaddr.IPv4('1.1.0.0/22'),
+                                     ipaddr.IPv4('1.1.4.0/24')])
+        # test that two addresses are supernet'ed properlly
+        collapsed = ipaddr.collapse_address_list([ip1, ip2])
+        self.assertEqual(collapsed, [ipaddr.IPv4('1.1.0.0/23')])
+
+        ip_same1 = ip_same2 = ipaddr.IPv4('1.1.1.1/32')
+        self.assertEqual(ipaddr.collapse_address_list([ip_same1, ip_same2]),
+                         [ip_same1])
+        ip1 = ipaddr.IPv6('::2001:1/100')
+        ip2 = ipaddr.IPv6('::2002:1/120')
+        ip3 = ipaddr.IPv6('::2001:1/96')
+        # test that ipv6 addresses are subsumed properly.
+        collapsed = ipaddr.collapse_address_list([ip1, ip2, ip3])
+        self.assertEqual(collapsed, [ip3])
+
+    def testNetworkComparison(self):
+        # ip1 and ip2 have the same network address
+        ip1 = ipaddr.IPv4('1.1.1.0/24')
+        ip2 = ipaddr.IPv4('1.1.1.1/24')
+        ip3 = ipaddr.IPv4('1.1.2.0/24')
+
+        self.assertTrue(ip1 < ip3)
+        self.assertTrue(ip3 > ip2)
+
+        self.assertEquals(ip1.compare_networks(ip2), 0)
+        self.assertTrue(ip1._get_networks_key() == ip2._get_networks_key())
+        self.assertEquals(ip1.compare_networks(ip3), -1)
+        self.assertTrue(ip1._get_networks_key() < ip3._get_networks_key())
+
+        ip1 = ipaddr.IPv6('2001::2000/96')
+        ip2 = ipaddr.IPv6('2001::2001/96')
+        ip3 = ipaddr.IPv6('2001:ffff::2000/96')
+
+        self.assertTrue(ip1 < ip3)
+        self.assertTrue(ip3 > ip2)
+        self.assertEquals(ip1.compare_networks(ip2), 0)
+        self.assertTrue(ip1._get_networks_key() == ip2._get_networks_key())
+        self.assertEquals(ip1.compare_networks(ip3), -1)
+        self.assertTrue(ip1._get_networks_key() < ip3._get_networks_key())
+
+        # Test comparing different protocols
+        ipv6 = ipaddr.IPv6('::/0')
+        ipv4 = ipaddr.IPv4('0.0.0.0/0')
+        self.assertTrue(ipv6 > ipv4)
+        self.assertTrue(ipv4 < ipv6)
+
+    def testEmbeddedIpv4(self):
+        ipv4_string = '192.168.0.1'
+        ipv4 = ipaddr.IPv4(ipv4_string)
+        v4compat_ipv6 = ipaddr.IPv6('::%s' % ipv4_string)
+        self.assertEquals(v4compat_ipv6.ip, ipv4.ip)
+        v4mapped_ipv6 = ipaddr.IPv6('::ffff:%s' % ipv4_string)
+        self.assertNotEquals(v4mapped_ipv6.ip, ipv4.ip)
+        self.assertRaises(ipaddr.IPv6IpValidationError, ipaddr.IPv6,
+                          '2001:1.1.1.1:1.1.1.1')
+
+    def testIPVersion(self):
+        self.assertEqual(self.ipv4.version, 4)
+        self.assertEqual(self.ipv6.version, 6)
+
+    def testPacked(self):
+        self.assertEqual(self.ipv4.packed,
+                         _cb('\x01\x02\x03\x04'))
+        self.assertEqual(ipaddr.IPv4('255.254.253.252').packed,
+                         _cb('\xff\xfe\xfd\xfc'))
+        self.assertEqual(self.ipv6.packed,
+                         _cb('\x20\x01\x06\x58\x02\x2a\xca\xfe'
+                             '\x02\x00\x00\x00\x00\x00\x00\x01'))
+        self.assertEqual(ipaddr.IPv6('ffff:2:3:4:ffff::').packed,
+                         _cb('\xff\xff\x00\x02\x00\x03\x00\x04\xff\xff'
+                            + '\x00' * 6))
+        self.assertEqual(ipaddr.IPv6('::1:0:0:0:0').packed,
+                         _cb('\x00' * 6 + '\x00\x01' + '\x00' * 8))
+
+    def testIpStrFromPrefixlen(self):
+        ipv4 = ipaddr.IPv4('1.2.3.4/24')
+        self.assertEquals(ipv4._ip_string_from_prefix(), '255.255.255.0')
+        self.assertEquals(ipv4._ip_string_from_prefix(28), '255.255.255.240')
+
+    def testIpType(self):
+        ipv4 = ipaddr.IP('1.2.3.4')
+        ipv6 = ipaddr.IP('::1.2.3.4')
+        self.assertEquals(ipaddr.IPv4, type(ipv4))
+        self.assertEquals(ipaddr.IPv6, type(ipv6))
+
+    def testReservedIpv4(self):
+        self.assertEquals(True, ipaddr.IP('224.1.1.1/31').is_multicast)
+        self.assertEquals(False, ipaddr.IP('240.0.0.0').is_multicast)
+
+        self.assertEquals(True, ipaddr.IP('192.168.1.1/17').is_private)
+        self.assertEquals(False, ipaddr.IP('192.169.0.0').is_private)
+        self.assertEquals(True, ipaddr.IP('10.255.255.255').is_private)
+        self.assertEquals(False, ipaddr.IP('11.0.0.0').is_private)
+        self.assertEquals(True, ipaddr.IP('172.31.255.255').is_private)
+        self.assertEquals(False, ipaddr.IP('172.32.0.0').is_private)
+
+        self.assertEquals(True, ipaddr.IP('169.254.100.200/24').is_link_local)
+        self.assertEquals(False, ipaddr.IP('169.255.100.200/24').is_link_local)
+
+        self.assertEquals(True, ipaddr.IP('127.100.200.254/32').is_loopback)
+        self.assertEquals(True, ipaddr.IP('127.42.0.0/16').is_loopback)
+        self.assertEquals(False, ipaddr.IP('128.0.0.0').is_loopback)
+
+    def testReservedIpv6(self):
+        ip = ipaddr.IP
+
+        self.assertEquals(True, ip('ffff::').is_multicast)
+        self.assertEquals(True, ip(2**128-1).is_multicast)
+        self.assertEquals(True, ip('ff00::').is_multicast)
+        self.assertEquals(False, ip('fdff::').is_multicast)
+
+        self.assertEquals(True, ip('fecf::').is_site_local)
+        self.assertEquals(True, ip('feff:ffff:ffff:ffff::').is_site_local)
+        self.assertEquals(False, ip('fbf:ffff::').is_site_local)
+        self.assertEquals(False, ip('ff00::').is_site_local)
+
+        self.assertEquals(True, ip('fc00::').is_private)
+        self.assertEquals(True, ip('fc00:ffff:ffff:ffff::').is_private)
+        self.assertEquals(False, ip('fbff:ffff::').is_private)
+        self.assertEquals(False, ip('fe00::').is_private)
+
+        self.assertEquals(True, ip('fea0::').is_link_local)
+        self.assertEquals(True, ip('febf:ffff::').is_link_local)
+        self.assertEquals(False, ip('fe7f:ffff::').is_link_local)
+        self.assertEquals(False, ip('fec0::').is_link_local)
+
+        self.assertEquals(True, ip('0:0::0:01').is_loopback)
+        self.assertEquals(False, ip('::1/127').is_loopback)
+        self.assertEquals(False, ip('::').is_loopback)
+        self.assertEquals(False, ip('::2').is_loopback)
+
+        self.assertEquals(True, ip('0::0').is_unspecified)
+        self.assertEquals(False, ip('::1').is_unspecified)
+        self.assertEquals(False, ip('::/127').is_unspecified)
+
+    def testAddrExclude(self):
+        addr1 = ipaddr.IP('10.1.1.0/24')
+        addr2 = ipaddr.IP('10.1.1.0/26')
+        addr3 = ipaddr.IP('10.2.1.0/24')
+        self.assertEqual(addr1.address_exclude(addr2),
+                         [ipaddr.IP('10.1.1.64/26'),
+                          ipaddr.IP('10.1.1.128/25')])
+        self.assertRaises(ValueError, addr1.address_exclude, addr3)
+
+    def testHash(self):
+        self.assertEquals(hash(ipaddr.IP('10.1.1.0/24')),
+                          hash(ipaddr.IP('10.1.1.0/24')))
+        dummy = {}
+        dummy[self.ipv4] = None
+        dummy[self.ipv6] = None
+        self.assertTrue(self.ipv4 in dummy)
+
+    def testIPv4PrefixFromInt(self):
+        addr1 = ipaddr.IP('10.1.1.0/24')
+        addr2 = ipaddr.IPv4(addr1.ip)  # clone prefix
+        addr2.prefixlen = addr1.prefixlen
+        addr3 = ipaddr.IP(123456)
+
+        self.assertEqual(123456, addr3.ip)
+        self.assertRaises(ipaddr.IPv4NetmaskValidationError,
+                          addr2._set_prefix, -1)
+        self.assertEqual(addr1, addr2)
+        self.assertEqual(str(addr1), str(addr2))
+
+    def testIPv6PrefixFromInt(self):
+        addr1 = ipaddr.IP('2001:0658:022a:cafe:0200::1/64')
+        addr2 = ipaddr.IPv6(addr1.ip)  # clone prefix
+        addr2.prefixlen = addr1.prefixlen
+        addr3 = ipaddr.IP(123456)
+
+        self.assertEqual(123456, addr3.ip)
+        self.assertRaises(ipaddr.IPv6NetmaskValidationError,
+                          addr2._set_prefix, -1)
+        self.assertEqual(addr1, addr2)
+        self.assertEqual(str(addr1), str(addr2))
+
+    def testCopyConstructor(self):
+        addr1 = ipaddr.IP('10.1.1.0/24')
+        addr2 = ipaddr.IP(addr1)
+        addr3 = ipaddr.IP('2001:658:22a:cafe:200::1/64')
+        addr4 = ipaddr.IP(addr3)
+
+        self.assertEqual(addr1, addr2)
+        self.assertEqual(addr3, addr4)
+
+    def testCompressIPv6Address(self):
+        test_addresses = {
+            '1:2:3:4:5:6:7:8': '1:2:3:4:5:6:7:8/128',
+            '2001:0:0:4:0:0:0:8': '2001:0:0:4::8/128',
+            '2001:0:0:4:5:6:7:8': '2001::4:5:6:7:8/128',
+            '2001:0:3:4:5:6:7:8': '2001:0:3:4:5:6:7:8/128',
+            '2001:0::3:4:5:6:7:8': '2001:0:3:4:5:6:7:8/128',
+            '0:0:3:0:0:0:0:ffff': '0:0:3::ffff/128',
+            '0:0:0:4:0:0:0:ffff': '::4:0:0:0:ffff/128',
+            '0:0:0:0:5:0:0:ffff': '::5:0:0:ffff/128',
+            '1:0:0:4:0:0:7:8': '1::4:0:0:7:8/128',
+            '0:0:0:0:0:0:0:0': '::/128',
+            '0:0:0:0:0:0:0:0/0': '::/0',
+            '0:0:0:0:0:0:0:1': '::1/128',
+            '2001:0658:022a:cafe:0000:0000:0000:0000/66':
+            '2001:658:22a:cafe::/66',
+            }
+        for uncompressed, compressed in test_addresses.items():
+            self.assertEquals(compressed, str(ipaddr.IPv6(uncompressed)))
+
+    def testExplodeShortHandIpStr(self):
+        addr1 = ipaddr.IPv6('2001::1')
+        self.assertEqual('2001:0000:0000:0000:0000:0000:0000:0001',
+                         addr1._explode_shorthand_ip_string(addr1.ip_ext))
+
+    def testIntRepresentation(self):
+        self.assertEqual(16909060, int(self.ipv4))
+        self.assertEqual(42540616829182469433547762482097946625, int(self.ipv6))
+
+    def testHexRepresentation(self):
+        self.assertEqual(hex(0x1020304), hex(self.ipv4))
+
+        self.assertEqual(hex(0x20010658022ACAFE0200000000000001),
+                         hex(self.ipv6))
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/Misc/NEWS b/Misc/NEWS
index 75d81fc..d2dcadd 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -261,6 +261,9 @@
 Library
 -------
 
+- Issue #3959: The ipaddr module has been added to the standard library.
+  Contributed by Google.
+
 - Issue #2245: aifc now skips chunk types it doesn't recognize, per spec.
 
 - Issue #5874: distutils.tests.test_config_cmd is not locale-sensitive