diff --git a/git_config.py b/git_config.py
index 163b080..53b52c8 100644
--- a/git_config.py
+++ b/git_config.py
@@ -337,12 +337,9 @@
 _ssh_cache = {}
 _ssh_master = True
 
-def _open_ssh(host, port=None):
+def _open_ssh(host, port):
   global _ssh_master
 
-  if port is None:
-    port = 22
-
   key = '%s:%s' % (host, port)
   if key in _ssh_cache:
     return True
@@ -397,6 +394,8 @@
     host = m.group(2)
     if ':' in host:
       host, port = host.split(':')
+    else:
+      port = 22
     if scheme in ('ssh', 'git+ssh', 'ssh+git'):
       return _open_ssh(host, port)
     return False
@@ -404,7 +403,7 @@
   m = URI_SCP.match(url)
   if m:
     host = m.group(1)
-    return _open_ssh(host)
+    return _open_ssh(host, 22)
 
 
 class Remote(object):