diff -up iptables-1.4.0/ip6tables.c.in6_u iptables-1.4.0/ip6tables.c
--- iptables-1.4.0/ip6tables.c.in6_u	2008-03-03 14:33:30.000000000 +0100
+++ iptables-1.4.0/ip6tables.c	2008-03-03 14:38:54.000000000 +0100
@@ -678,7 +678,7 @@ parse_hostnetworkmask(const char *name, 
 	for (i = 0, j = 0; i < n; i++) {
 		int k;
 		for (k = 0; k < 4; k++)
-			addrp[j].in6_u.u6_addr32[k] &= maskp->in6_u.u6_addr32[k];
+			addrp[j].s6_addr32[k] &= maskp->s6_addr32[k];
 		j++;
 		for (k = 0; k < j - 1; k++) {
 			if (IN6_ARE_ADDR_EQUAL(&addrp[k], &addrp[j - 1])) {
diff -up iptables-1.4.0/libiptc/libip6tc.c.in6_u iptables-1.4.0/libiptc/libip6tc.c
--- iptables-1.4.0/libiptc/libip6tc.c.in6_u	2008-03-03 14:33:31.000000000 +0100
+++ iptables-1.4.0/libiptc/libip6tc.c	2008-03-03 14:33:31.000000000 +0100
@@ -113,7 +113,7 @@ typedef unsigned int socklen_t;
 #include "libiptc.c"
 
 #define BIT6(a, l) \
- ((ntohl(a->in6_u.u6_addr32[(l) / 32]) >> (31 - ((l) & 31))) & 1)
+ ((ntohl(a->s6_addr32[(l) / 32]) >> (31 - ((l) & 31))) & 1)
 
 int
 ipv6_prefix_length(const struct in6_addr *a)