Index: sys/netpfil/ipfw/nat64/nat64_translate.c
===================================================================
--- sys/netpfil/ipfw/nat64/nat64_translate.c
+++ sys/netpfil/ipfw/nat64/nat64_translate.c
@@ -1061,19 +1061,16 @@
 		    m->m_pkthdr.len);
 		goto freeit;
 	}
-#if 0
 	/*
 	 * Check that inner source matches the outer destination.
-	 * XXX: We need some method to convert IPv4 into IPv6 address here,
-	 *	and compare IPv6 addresses.
 	 */
-	if (ip.ip_src.s_addr != nat64_get_ip4(&ip6->ip6_dst)) {
-		DPRINTF(DP_GENERIC, "Inner source doesn't match destination ",
+	if (ip.ip_src.s_addr !=
+	    nat64_extract_ip4(&ip6->ip6_dst, cfg->plat_plen)) {
+		DPRINTF(DP_GENERIC, "Inner source doesn't match destination: "
 		    "%04x vs %04x", ip.ip_src.s_addr,
-		    nat64_get_ip4(&ip6->ip6_dst));
+		    nat64_extract_ip4(&ip6->ip6_dst, cfg->plat_plen));
 		goto freeit;
 	}
-#endif
 	/*
 	 * Create new mbuf for ICMPv6 datagram.
 	 * NOTE: len is data length just after inner IP header.