diff -r c919a82b5a40 Lib/test/test_uuid.py
--- a/Lib/test/test_uuid.py	Mon Mar 14 10:56:33 2011 -0400
+++ b/Lib/test/test_uuid.py	Mon Mar 14 17:21:28 2011 -0400
@@ -360,6 +360,39 @@
 
         self.assertEqual(node1, node2)
 
+    def test__find_mac(self):
+        import os
+
+        original_popen = os.popen
+
+        class MockPopen(object):
+            data = [
+                ('cscotun0  Link encap:UNSPEC  HWaddr '
+                 '00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00'),
+                'eth0      Link encap:Ethernet  HWaddr 12:34:56:78:90:ab',
+            ]
+            def __init__(self, cmd):
+                pass
+            def __enter__(self):
+                return self
+            def __exit__(self, exc_type, exc_value, traceback):
+                pass
+            def __iter__(self):
+                return iter(self.data)
+
+        os.popen = MockPopen
+
+        try:
+            mac = uuid._find_mac(
+                command='ifconfig',
+                args='',
+                hw_identifiers=['hwaddr'],
+                get_index=lambda x: x + 1,
+            )
+            self.assertEqual(mac, 0x1234567890ab)
+        finally:
+            os.popen = original_popen
+
     def test_uuid1(self):
         # uuid1 requires ctypes.
         try:
diff -r c919a82b5a40 Lib/uuid.py
--- a/Lib/uuid.py	Mon Mar 14 10:56:33 2011 -0400
+++ b/Lib/uuid.py	Mon Mar 14 17:21:28 2011 -0400
@@ -327,8 +327,16 @@
                     words = line.lower().split()
                     for i in range(len(words)):
                         if words[i] in hw_identifiers:
-                            return int(
-                                words[get_index(i)].replace(':', ''), 16)
+                            try:
+                                return int(
+                                    words[get_index(i)].replace(':', ''), 16)
+                            # Virtual interfaces, such as those provided by
+                            # VPNs, do not have a colon-delimited MAC address
+                            # as expected, but a 16-byte HWAddr separated by
+                            # dashes. These should be ignored in favor of a
+                            # real MAC address
+                            except ValueError:
+                                continue
         except IOError:
             continue
     return None
diff -r c919a82b5a40 Misc/ACKS
--- a/Misc/ACKS	Mon Mar 14 10:56:33 2011 -0400
+++ b/Misc/ACKS	Mon Mar 14 17:21:28 2011 -0400
@@ -285,6 +285,7 @@
 Doug Fort
 John Fouhy
 Martin Franklin
+Kent Frazier
 Robin Friedrich
 Ivan Frohne
 Jim Fulton