diff --git a/src/core/ipv6/nd6.c b/src/core/ipv6/nd6.c
index 8b24180b..ec29a9bb 100644
--- a/src/core/ipv6/nd6.c
+++ b/src/core/ipv6/nd6.c
@@ -485,7 +485,9 @@ nd6_input(struct pbuf *p, struct netif *inp)
         struct prefix_option *prefix_opt;
         prefix_opt = (struct prefix_option *)buffer;
 
-        if (prefix_opt->flags & ND6_PREFIX_FLAG_ON_LINK) {
+        if ((prefix_opt->flags & ND6_PREFIX_FLAG_ON_LINK) &&
+            (prefix_opt->length == 64)  &&
+            !ip6_addr_islinklocal(&(prefix_opt->prefix))) {
           /* Add to on-link prefix list. */
           s8_t prefix;