diff -uNr a/vpnc-script b/vpnc-script
--- a/vpnc-script	2015-09-06 13:19:11.408661526 +0200
+++ b/vpnc-script	2015-09-06 14:47:40.260871556 +0200
@@ -647,7 +647,7 @@
 			echo "$i" | grep : >/dev/null || \
 				set_network_route "$i" "255.255.255.255" "32"
 		done
-	elif [ -n "$INTERNAL_IP4_ADDRESS" ]; then
+	elif [ -n "$INTERNAL_IP4_ADDRESS" -a -z "$INTERNAL_IP4_NETMASK" ]; then
 		set_default_route
 	fi
 	if [ -n "$CISCO_IPV6_SPLIT_INC" ]; then