diff -ruN ipt-orig/extensions/libipt_REDIRECT.c ipt-new/extensions/libipt_REDIRECT.c
--- ipt-orig/extensions/libipt_REDIRECT.c	2005-07-21 23:39:45.000000000 -0700
+++ ipt-new/extensions/libipt_REDIRECT.c	2006-06-19 18:14:37.000000000 -0700
@@ -44,6 +44,9 @@
 
 	mr->range[0].flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
 
+	if (strchr(arg, '.'))
+		exit_error(PARAMETER_PROBLEM, "IP address not permitted\n");
+
 	port = atoi(arg);
 	if (port == 0 || port > 65535)
 		exit_error(PARAMETER_PROBLEM, "Port `%s' not valid\n", arg);