diff --git a/src/core/udp.c b/src/core/udp.c
index cda8acea..f88cf773 100644
--- a/src/core/udp.c
+++ b/src/core/udp.c
@@ -570,9 +570,6 @@ udp_sendto_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip,
 #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
   struct netif *netif;
   const ip_addr_t *dst_ip_route = dst_ip;
-#if LWIP_IPV6 && LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS
-  ip_addr_t dst_ip_tmp;
-#endif /* LWIP_IPV6 && LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS */
 
   if ((pcb == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, dst_ip)) {
     return ERR_VAL;
@@ -594,10 +591,9 @@ udp_sendto_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip,
          administratively selected interface for multicast by default.
          However, this can be overridden by setting an interface address
          in pcb->multicast_ip that is used for routing. */
-      if (!ip4_addr_isany(&pcb->multicast_ip) &&
-          !ip4_addr_cmp(&pcb->multicast_ip, IP4_ADDR_BROADCAST)) {
-        ip_addr_copy_from_ip4(dst_ip_tmp, pcb->multicast_ip);
-        dst_ip_route = &dst_ip_tmp;
+      if (!ip_addr_isany(&pcb->multicast_ip) &&
+          !ip4_addr_cmp(ip_2_ip4(&pcb->multicast_ip), IP4_ADDR_BROADCAST)) {
+        dst_ip_route = & pcb->multicast_ip;
       }
 #endif /* LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS */
     }
diff --git a/src/include/lwip/udp.h b/src/include/lwip/udp.h
index f4dc0ef3..7c4a3dbf 100644
--- a/src/include/lwip/udp.h
+++ b/src/include/lwip/udp.h
@@ -102,7 +102,7 @@ struct udp_pcb {
 
 #if LWIP_MULTICAST_TX_OPTIONS
   /** outgoing network interface for multicast packets */
-  ip4_addr_t multicast_ip;
+  ip_addr_t multicast_ip;
   /** TTL for outgoing multicast packets */
   u8_t mcast_ttl;
 #endif /* LWIP_MULTICAST_TX_OPTIONS */
@@ -169,8 +169,8 @@ struct udp_pcb * udp_new_ip6(void);
 #endif /* LWIP_IPV6 */
 
 #if LWIP_MULTICAST_TX_OPTIONS
-#define udp_set_multicast_netif_addr(pcb, ip4addr) do { (pcb)->multicast_ip = *(ip4addr); } while(0)
-#define udp_get_multicast_netif_addr(pcb)          (&(pcb)->multicast_ip)
+#define udp_set_multicast_netif_addr(pcb, ip4addr) ip_addr_copy_from_ip4((pcb)->multicast_ip, *(ip4addr))
+#define udp_get_multicast_netif_addr(pcb)          ip_2_ip4(&(pcb)->multicast_ip)
 #define udp_set_multicast_ttl(pcb, value)      do { (pcb)->mcast_ttl = value; } while(0)
 #define udp_get_multicast_ttl(pcb)                 ((pcb)->mcast_ttl)
 #endif /* LWIP_MULTICAST_TX_OPTIONS */