--- a/src/cssh.pl
+++ b/src/cssh.pl
@@ -937,7 +937,7 @@
 
     # check for correct syntax of using [<IPv6 address>]
     # See http://tools.ietf.org/html/rfc2732 for more details
-    if ( $connect_string =~ m/^\[([\w:]+)\](?::(\d+))?$/xsm ) {
+    if ( $connect_string =~ m/^\[([\w:%]+)\](?::(\d+))?$/xsm ) {
         logmsg( 3, 'connect_string contains IPv6 address' );
         $server = $1;
         $port   = $2;
@@ -975,7 +975,7 @@
                # method will warn if it cannot connect anyhow
                # However, this also catchs IPv4 addresses, possibly with ports
                 ( $server, $port )
-                    = $connect_string =~ m/^([\w.-]+)(?::(\d+))?$/xsm;
+                    = $connect_string =~ m/^([\w%.-]+)(?::(\d+))?$/xsm;
             }
         }
     }