diff --git a/Lib/urllib.py b/Lib/urllib.py
index aac235d..1261ec1 100644
--- a/Lib/urllib.py
+++ b/Lib/urllib.py
@@ -1366,7 +1366,8 @@
     # strip port off host
     hostonly, port = splitport(host)
     # check if the host ends with any of the DNS suffixes
-    for name in no_proxy.split(','):
+    no_proxy_list = [proxy.strip() for proxy in no_proxy.split(',')]
+    for name in no_proxy_list:
         if name and (hostonly.endswith(name) or host.endswith(name)):
             return 1
     # otherwise, don't bypass