diff --git a/ripngd/ripng_nexthop.h b/ripngd/ripng_nexthop.h
index 2213fc2..50a86ad 100644
--- a/ripngd/ripng_nexthop.h
+++ b/ripngd/ripng_nexthop.h
@@ -43,7 +43,12 @@
 addr6_cmp(struct in6_addr *A, struct in6_addr *B) {
 
 #ifndef s6_addr32
+#if defined(SUNOS_5)
+/* Some SunOS define s6_addr32 only to kernel */
+#define s6_addr32 _S6_un._S6_u32
+#else
 #define s6_addr32 __u6_addr.__u6_addr32
+#endif /* SUNOS_5 */
 #endif /*s6_addr32*/
 
 #define a(i) A->s6_addr32[i]