Index: sbin/ipfw/ipfw.8
===================================================================
--- sbin/ipfw/ipfw.8
+++ sbin/ipfw/ipfw.8
@@ -3571,6 +3571,13 @@
 Turn off private address handling in
 .Nm nat64clat
 instance.
+.It Cm local
+Create UE (client) instance for packets originating from the local node.
+.It Cm -local
+Create external (router) instance for packets originating from network.
+This is the default behavior for
+.Nm nat64clat
+instance.
 .El
 .Pp
 Note that the behavior of CLAT translator with respect to not matched
Index: sbin/ipfw/ipfw2.h
===================================================================
--- sbin/ipfw/ipfw2.h
+++ sbin/ipfw/ipfw2.h
@@ -295,6 +295,8 @@
 	TOK_LOGOFF,
 	TOK_PRIVATE,
 	TOK_PRIVATEOFF,
+	TOK_LOCAL,
+	TOK_LOCALOFF,
 
 	/* NAT64 CLAT tokens */
 	TOK_NAT64CLAT,
Index: sbin/ipfw/nat64clat.c
===================================================================
--- sbin/ipfw/nat64clat.c
+++ sbin/ipfw/nat64clat.c
@@ -166,6 +166,8 @@
       { "-log",		TOK_LOGOFF },
       { "allow_private", TOK_PRIVATE },
       { "-allow_private", TOK_PRIVATEOFF },
+      { "local",	TOK_LOCAL },
+      { "-local",	TOK_LOCALOFF },
       { NULL, 0 }
 };
 
@@ -241,6 +243,12 @@
 		case TOK_PRIVATEOFF:
 			cfg->flags &= ~NAT64_ALLOW_PRIVATE;
 			break;
+		case TOK_LOCAL:
+			cfg->flags |= NAT64_LOCAL;
+			break;
+		case TOK_LOCALOFF:
+			cfg->flags &= ~NAT64_LOCAL;
+			break;
 		}
 	}
 
@@ -331,6 +339,12 @@
 		case TOK_PRIVATEOFF:
 			cfg->flags &= ~NAT64_ALLOW_PRIVATE;
 			break;
+		case TOK_LOCAL:
+			cfg->flags |= NAT64_LOCAL;
+			break;
+		case TOK_LOCALOFF:
+			cfg->flags &= ~NAT64_LOCAL;
+			break;
 		default:
 			errx(EX_USAGE, "Can't change %s option", opt);
 		}
@@ -452,6 +466,8 @@
 		printf(" log");
 	if (cfg->flags & NAT64_ALLOW_PRIVATE)
 		printf(" allow_private");
+	if (cfg->flags & NAT64_LOCAL)
+		printf(" local");
 	printf("\n");
 	return (0);
 }
Index: sys/netinet6/ip_fw_nat64.h
===================================================================
--- sys/netinet6/ip_fw_nat64.h
+++ sys/netinet6/ip_fw_nat64.h
@@ -97,6 +97,7 @@
 #define	NAT64_ALLOW_PRIVATE	0x0002	/* Allow private IPv4 address
 					 * translation
 					 */
+#define	NAT64_LOCAL		0x0004	/* Compute full checksum */
 typedef struct _ipfw_nat64stl_cfg {
 	char		name[64];	/* NAT name			*/
 	ipfw_obj_ntlv	ntlv6;		/* object name tlv		*/
Index: sys/netpfil/ipfw/nat64/nat64_translate.h
===================================================================
--- sys/netpfil/ipfw/nat64/nat64_translate.h
+++ sys/netpfil/ipfw/nat64/nat64_translate.h
@@ -149,6 +149,7 @@
     uint16_t aport, struct nat64_config *cfg, void *logdata);
 void nat64_embed_ip4(struct in6_addr *ip6, int plen, in_addr_t ia);
 in_addr_t nat64_extract_ip4(const struct in6_addr *ip6, int plen);
+void nat64_local_csum(struct mbuf *m);
 
 void nat64_set_output_method(int);
 int nat64_get_output_method(void);
Index: sys/netpfil/ipfw/nat64/nat64_translate.c
===================================================================
--- sys/netpfil/ipfw/nat64/nat64_translate.c
+++ sys/netpfil/ipfw/nat64/nat64_translate.c
@@ -1298,6 +1298,8 @@
 	switch (proto) {
 	case IPPROTO_TCP:
 		csum = &TCP(mtodo(m, hlen))->th_sum;
+		if (cfg->flags & NAT64_LOCAL)
+			nat64_local_csum(m);
 		if (lport != 0) {
 			struct tcphdr *tcp = TCP(mtodo(m, hlen));
 			*csum = cksum_adjust(*csum, tcp->th_dport, lport);
@@ -1307,6 +1309,8 @@
 		break;
 	case IPPROTO_UDP:
 		csum = &UDP(mtodo(m, hlen))->uh_sum;
+		if (cfg->flags & NAT64_LOCAL)
+			nat64_local_csum(m);
 		if (lport != 0) {
 			struct udphdr *udp = UDP(mtodo(m, hlen));
 			*csum = cksum_adjust(*csum, udp->uh_dport, lport);
@@ -1331,6 +1335,16 @@
 	}
 	mbufq_drain(&mq);
 	return (NAT64RETURN);
+}
+
+void
+nat64_local_csum(struct mbuf *m)
+{
+	if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
+		m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
+
+	in_delayed_cksum(m);
+	m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 }
 
 int
Index: sys/netpfil/ipfw/nat64/nat64clat.h
===================================================================
--- sys/netpfil/ipfw/nat64/nat64clat.h
+++ sys/netpfil/ipfw/nat64/nat64clat.h
@@ -39,8 +39,9 @@
 	struct named_object	no;
 
 	struct nat64_config	base;
+	/* flags to pass to userland */
 #define	NAT64CLAT_FLAGSMASK	\
-	(NAT64_LOG | NAT64_ALLOW_PRIVATE) /* flags to pass to userland */
+	(NAT64_LOG | NAT64_ALLOW_PRIVATE | NAT64_LOCAL)
 	char			name[64];
 };
 
Index: sys/netpfil/ipfw/nat64/nat64lsn.h
===================================================================
--- sys/netpfil/ipfw/nat64/nat64lsn.h
+++ sys/netpfil/ipfw/nat64/nat64lsn.h
@@ -218,7 +218,7 @@
 	uint16_t	st_icmp_ttl;	/* ICMP expire */
 
 	struct nat64_config	base;
-#define	NAT64LSN_FLAGSMASK	(NAT64_LOG | NAT64_ALLOW_PRIVATE)
+#define	NAT64LSN_FLAGSMASK	(NAT64_LOG | NAT64_ALLOW_PRIVATE | NAT64_LOCAL)
 #define	NAT64LSN_ANYPREFIX	0x00000100
 
 	struct mtx		periodic_lock;
Index: sys/netpfil/ipfw/nat64/nat64stl.h
===================================================================
--- sys/netpfil/ipfw/nat64/nat64stl.h
+++ sys/netpfil/ipfw/nat64/nat64stl.h
@@ -45,7 +45,7 @@
 #define	NAT64STL_46T		0x0200
 #define	NAT64STL_64T		0x0400
 	/* flags to pass to userland */
-#define	NAT64STL_FLAGSMASK	(NAT64_LOG | NAT64_ALLOW_PRIVATE)
+#define	NAT64STL_FLAGSMASK	(NAT64_LOG | NAT64_ALLOW_PRIVATE | NAT64_LOCAL)
 	char			name[64];
 };