diff --git a/source4/libcli/nbt/libnbt.h b/source4/libcli/nbt/libnbt.h
index 88ca0e204bf..524391917d6 100644
--- a/source4/libcli/nbt/libnbt.h
+++ b/source4/libcli/nbt/libnbt.h
@@ -163,6 +163,7 @@ struct nbt_name_register {
 	struct {
 		struct nbt_name name;
 		const char *dest_addr;
+		uint16_t dest_port;
 		const char *address;
 		uint16_t nb_flags;
 		bool register_demand;
diff --git a/source4/libcli/nbt/nameregister.c b/source4/libcli/nbt/nameregister.c
index fd4a94dd44e..9389981647d 100644
--- a/source4/libcli/nbt/nameregister.c
+++ b/source4/libcli/nbt/nameregister.c
@@ -77,7 +77,7 @@ struct nbt_name_request *nbt_name_register_send(struct nbt_name_socket *nbtsock,
 	if (packet->additional[0].rdata.netbios.addresses[0].ipaddr == NULL) goto failed;
 
 	dest = socket_address_from_strings(packet, nbtsock->sock->backend_name, 
-					   io->in.dest_addr, lp_nbt_port(global_loadparm));
+					   io->in.dest_addr, io->in.dest_port);
 	if (dest == NULL) goto failed;
 	req = nbt_name_request_send(nbtsock, dest, packet,
 				    io->in.timeout, io->in.retries, false);
@@ -224,6 +224,7 @@ struct composite_context *nbt_name_register_bcast_send(struct nbt_name_socket *n
 
 	state->io->in.name            = io->in.name;
 	state->io->in.dest_addr       = io->in.dest_addr;
+	state->io->in.dest_port       = lp_nbt_port(global_loadparm);
 	state->io->in.address         = io->in.address;
 	state->io->in.nb_flags        = io->in.nb_flags;
 	state->io->in.register_demand = false;
@@ -311,6 +312,7 @@ static void name_register_wins_handler(struct nbt_name_request *req)
 			goto done;
 		}
 		state->io->in.dest_addr = state->wins_servers[0];
+		state->io->in.dest_port = lp_nbt_port(global_loadparm);
 		state->io->in.address   = state->addresses[0];
 		state->req = nbt_name_register_send(state->nbtsock, state->io);
 		if (state->req == NULL) {
@@ -377,6 +379,7 @@ struct composite_context *nbt_name_register_wins_send(struct nbt_name_socket *nb
 
 	state->io->in.name            = io->in.name;
 	state->io->in.dest_addr       = state->wins_servers[0];
+	state->io->in.dest_port       = lp_nbt_port(global_loadparm);
 	state->io->in.address         = io->in.addresses[0];
 	state->io->in.nb_flags        = io->in.nb_flags;
 	state->io->in.broadcast       = false;
diff --git a/source4/nbt_server/register.c b/source4/nbt_server/register.c
index c185001e23d..bde9b1e2db8 100644
--- a/source4/nbt_server/register.c
+++ b/source4/nbt_server/register.c
@@ -93,6 +93,7 @@ static void name_refresh_handler(struct event_context *ev, struct timed_event *t
 	   registration packets */
 	io.in.name            = iname->name;
 	io.in.dest_addr       = iface->bcast_address;
+	io.in.dest_port       = lp_nbt_port(iface->nbtsrv->task->lp_ctx);
 	io.in.address         = iface->ip_address;
 	io.in.nb_flags        = iname->nb_flags;
 	io.in.ttl             = iname->ttl;
diff --git a/source4/torture/nbt/register.c b/source4/torture/nbt/register.c
index c7f992cbd60..2c37d9de501 100644
--- a/source4/torture/nbt/register.c
+++ b/source4/torture/nbt/register.c
@@ -67,6 +67,7 @@ static bool nbt_register_own(struct torture_context *tctx)
 
 	io.in.name = name;
 	io.in.dest_addr = address;
+	io.in.dest_port = lp_nbt_port(tctx->lp_ctx);
 	io.in.address = myaddress;
 	io.in.nb_flags = NBT_NODE_B | NBT_NM_ACTIVE;
 	io.in.register_demand = false;
diff --git a/source4/torture/nbt/winsbench.c b/source4/torture/nbt/winsbench.c
index 82223d9dd7a..d49b50b9d3a 100644
--- a/source4/torture/nbt/winsbench.c
+++ b/source4/torture/nbt/winsbench.c
@@ -87,6 +87,7 @@ static void generate_register(struct nbt_name_socket *nbtsock, struct wins_state
 
 	io.in.name            = generate_name(tmp_ctx, idx);
 	io.in.dest_addr       = state->wins_server;
+	io.in.dest_port       = lp_nbt_port(global_loadparm);
 	io.in.address         = state->my_ip;
 	io.in.nb_flags        = NBT_NODE_H;
 	io.in.register_demand = false;
diff --git a/source4/torture/nbt/winsreplication.c b/source4/torture/nbt/winsreplication.c
index b427843b80e..f67b6050f27 100644
--- a/source4/torture/nbt/winsreplication.c
+++ b/source4/torture/nbt/winsreplication.c
@@ -6530,6 +6530,7 @@ static bool test_conflict_owned_released_vs_replica(struct torture_context *tctx
 		 */
 		name_register->in.name		= records[i].name;
 		name_register->in.dest_addr	= ctx->address;
+		name_register->in.dest_port	= lp_nbt_port(tctx->lp_ctx);
 		name_register->in.address	= records[i].wins.ips[0].ip;
 		name_register->in.nb_flags	= records[i].wins.nb_flags;
 		name_register->in.register_demand= false;
@@ -9218,6 +9219,7 @@ static bool test_conflict_owned_active_vs_replica(struct torture_context *tctx,
 
 			name_register->in.name		= records[i].name;
 			name_register->in.dest_addr	= ctx->address;
+			name_register->in.dest_port     = lp_nbt_port(tctx->lp_ctx);
 			name_register->in.address	= records[i].wins.ips[j].ip;
 			name_register->in.nb_flags	= records[i].wins.nb_flags;
 			name_register->in.register_demand= false;