diff --git a/ospf6d/ospf6_message.c b/ospf6d/ospf6_message.c
index ecc96f7..e71b410 100644
--- a/ospf6d/ospf6_message.c
+++ b/ospf6d/ospf6_message.c
@@ -1630,7 +1630,7 @@
 ospf6_send (struct in6_addr *src, struct in6_addr *dst,
             struct ospf6_interface *oi, struct ospf6_header *oh)
 {
-  int len;
+  unsigned int len;
   char srcname[64], dstname[64];
   struct iovec iovector[2];