diff --git a/Lib/urllib.py b/Lib/urllib.py
index 2ba5590..123642a 100644
--- a/Lib/urllib.py
+++ b/Lib/urllib.py
@@ -1278,7 +1278,11 @@
                     # Per-protocol settings
                     for p in proxyServer.split(';'):
                         protocol, address = p.split('=', 1)
-                        proxies[protocol] = '%s://%s' % (protocol, address)
+                        # See if address has a type:// prefix
+                        type, address = splittype(address)
+                        if not type:
+                            address = '%s://%s' % (protocol, address)
+                        proxies[protocol] = address
                 else:
                     # Use one setting for all protocols
                     if proxyServer[:5] == 'http:':