diff --git a/Lib/urllib.py b/Lib/urllib.py
index e1fa743828c7..aeca3f100734 100644
--- a/Lib/urllib.py
+++ b/Lib/urllib.py
@@ -1403,13 +1403,20 @@ def proxy_bypass(host):
         if not proxyEnable or not proxyOverride:
             return 0
         # try to make a host list from name and IP address.
-        host = [host]
+        rawHost, port = splitport(host)
+        host = [rawHost]
         try:
-            addr = socket.gethostbyname(host[0])
-            if addr != host:
+            addr = socket.gethostbyname(rawHost)
+            if addr != rawHost:
                 host.append(addr)
         except socket.error:
             pass
+        try:
+            fqdn = socket.getfqdn(rawHost)
+            if fqdn != rawHost:
+                host.append(fqdn)
+        except socket.error:
+            pass
         # make a check value list from the registry entry: replace the
         # '<local>' string by the localhost entry and the corresponding
         # canonical entry.