diff --git a/Shorewall-perl/Shorewall/Tunnels.pm b/Shorewall-perl/Shorewall/Tunnels.pm
index 6c38a693c..7317b0837 100644
--- a/Shorewall-perl/Shorewall/Tunnels.pm
+++ b/Shorewall-perl/Shorewall/Tunnels.pm
@@ -63,7 +63,7 @@ sub setup_tunnels() {
 	add_rule $outchainref,  "-p udp $dest --dport 500 $options";
 
 	if ( $kind eq 'ipsec' ) {
-	    add_rule $inchainref, "-p udp $source --dport $options";
+	    add_rule $inchainref, "-p udp $source --dport 500 $options";
 	} else {
 	    add_rule $inchainref,  "-p udp $source -m multiport --dports 500,4500 $options";
 	    add_rule $outchainref, "-p udp $dest   -m multiport --dports 500,4500 $options";