diff --git a/mininet/node.py b/mininet/node.py
index 3185746..a737845 100644
--- a/mininet/node.py
+++ b/mininet/node.py
@@ -1140,7 +1140,7 @@ class Controller( Node ):
                              "installed." )
         listening = self.cmd( "echo A | telnet -e A %s %d" %
                               ( self.ip, self.port ) )
-        if 'Unable' not in listening:
+        if 'refused' not in listening:
             servers = self.cmd( 'netstat -atp' ).split( '\n' )
             pstr = ':%d ' % self.port
             clist = servers[ 0:1 ] + [ s for s in servers if pstr in s ]
@@ -1235,6 +1235,6 @@ class RemoteController( Controller ):
         "Warn if remote controller is not accessible"
         listening = self.cmd( "echo A | telnet -e A %s %d" %
                               ( self.ip, self.port ) )
-        if 'Unable' in listening:
+        if 'refused' in listening:
             warn( "Unable to contact the remote controller"
                   " at %s:%d\n" % ( self.ip, self.port ) )