diff --git a/src/include/lwip/prot/dhcp6.h b/src/include/lwip/prot/dhcp6.h
index 0754c91b..9dab83ab 100644
--- a/src/include/lwip/prot/dhcp6.h
+++ b/src/include/lwip/prot/dhcp6.h
@@ -129,6 +129,7 @@ typedef enum {
 #define DHCP6_OPTION_DNS_SERVERS    23 /* RFC 3646 */
 #define DHCP6_OPTION_DOMAIN_LIST    24 /* RFC 3646 */
 #define DHCP6_OPTION_SNTP_SERVERS   31 /* RFC 4075 */
+#define DHCP6_OPTION_MUD_URL_V6     112 /* RFC 8520 */
 
 
 #ifdef __cplusplus