diff --git a/tests/lwip_sock_ip/stack.c b/tests/lwip_sock_ip/stack.c
index e4c91671eb..7dfd18879e 100644
--- a/tests/lwip_sock_ip/stack.c
+++ b/tests/lwip_sock_ip/stack.c
@@ -235,6 +235,8 @@ void _prepare_send_checks(void)
         if (nc->state == ND6_NO_ENTRY) {
             nc->state = ND6_REACHABLE;
             memcpy(&nc->next_hop_address, remote6, sizeof(ip6_addr_t));
+            ip6_addr_assign_zone(&nc->next_hop_address,
+                                 IP6_UNICAST, &netif);
             memcpy(&nc->lladdr, mac, 6);
             nc->netif = &netif;
             nc->counter.reachable_time = UINT32_MAX;
diff --git a/tests/lwip_sock_udp/stack.c b/tests/lwip_sock_udp/stack.c
index 4ac890b6e3..d109e35248 100644
--- a/tests/lwip_sock_udp/stack.c
+++ b/tests/lwip_sock_udp/stack.c
@@ -237,6 +237,8 @@ void _prepare_send_checks(void)
         if (nc->state == ND6_NO_ENTRY) {
             nc->state = ND6_REACHABLE;
             memcpy(&nc->next_hop_address, remote6, sizeof(ip6_addr_t));
+            ip6_addr_assign_zone(&nc->next_hop_address,
+                                 IP6_UNICAST, &netif);
             memcpy(&nc->lladdr, mac, 6);
             nc->netif = &netif;
             nc->counter.reachable_time = UINT32_MAX;