diff --git a/Shorewall/Perl/Shorewall/Tc.pm b/Shorewall/Perl/Shorewall/Tc.pm
index 7781fd13f..ba993dc99 100644
--- a/Shorewall/Perl/Shorewall/Tc.pm
+++ b/Shorewall/Perl/Shorewall/Tc.pm
@@ -458,7 +458,7 @@ our  %tccmd;
 						  if ( $ip =~ /^\[(.+)\]$/ || $ip =~ /^<(.+)>$/ ) {
 						      $ip = $1;
 						  } elsif ( $ip =~ /^\[(.+)\]\/(\d+)$/ ) {
-						      $ip = join( $1, $2 );
+						      $ip = join( '/', $1, $2 );
 						  }
 					      }