--- /tmp/urllib.py	2010-12-07 15:00:22.000000000 +0800
+++ /opt/local/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/urllib.py	2010-12-07 15:00:33.000000000 +0800
@@ -1376,7 +1376,7 @@
                         continue
 
                 base = ip2num(m.group(1))
-                mask = int(m.group(2)[1:])
+                mask = int(m.group(2)[1:]) if m.group(2) else 32
                 mask = 32 - mask
 
                 if (hostIP >> mask) == (base >> mask):