--- ipt-orig/iptables.c	2006-02-11 01:50:11.000000000 -0800
+++ ipt-new/iptables.c	2006-02-19 21:46:03.000000000 -0800
@@ -2125,6 +2125,11 @@
 				exit_error(PARAMETER_PROBLEM,
 					   "unexpected ! flag before --match");
 
+			for (matchp = matches; matchp; matchp = matchp->next) {
+				if (strcmp(optarg, matchp->match->name) == 0)
+					exit_error(PARAMETER_PROBLEM,
+						   "multiple matches of same type not supported");
+			}
 			m = find_match(optarg, LOAD_MUST_SUCCEED, &matches);
 			size = IPT_ALIGN(sizeof(struct ipt_entry_match))
 					 + m->size;