diff --git a/proto/ospf/iface.c b/proto/ospf/iface.c
index 448b08d1..fcac697e 100644
--- a/proto/ospf/iface.c
+++ b/proto/ospf/iface.c
@@ -89,6 +89,7 @@ ospf_sk_open(struct ospf_iface *ifa)
   sk->tbsize = rxbufsize(ifa);
   sk->data = (void *) ifa;
   sk->flags = SKF_LADDR_RX | (ifa->check_ttl ? SKF_TTL_RX : 0);
+  sk->ttl = ifa->cf->ttl_security ? 255 : -1;
 
   if (sk_open(sk) != 0)
     goto err;
@@ -652,7 +653,8 @@ ospf_iface_reconfigure(struct ospf_iface *ifa, struct ospf_iface_patt *new)
   /* Change of these options would require to reset the iface socket */
   if ((new->real_bcast != ifa->cf->real_bcast) ||
       (new->tx_tos != ifa->cf->tx_tos) ||
-      (new->tx_priority != ifa->cf->tx_priority))
+      (new->tx_priority != ifa->cf->tx_priority) ||
+      (new->ttl_security != ifa->cf->ttl_security))
     return 0;
 
   ifa->cf = new;
diff --git a/sysdep/bsd/sysio.h b/sysdep/bsd/sysio.h
index e33bc9c6..6de32919 100644
--- a/sysdep/bsd/sysio.h
+++ b/sysdep/bsd/sysio.h
@@ -6,6 +6,18 @@
  *	Can be freely distributed and used under the terms of the GNU GPL.
  */
 
+#ifdef __NetBSD__
+
+#ifndef IP_RECVTTL
+#define IP_RECVTTL 23
+#endif
+
+#ifndef IP_MINTTL
+#define IP_MINTTL 24
+#endif
+
+#endif
+
 #ifdef __DragonFly__
 #define TCP_MD5SIG	TCP_SIGNATURE_ENABLE
 #endif
@@ -211,8 +223,6 @@ sk_set_md5_auth_int(sock *s, struct sockaddr *sa, int sa_len, char *passwd)
 }
 
 
-#ifdef IP_MINTTL
-
 static inline char *
 sk_set_min_ttl4(sock *s, int ttl)
 {
@@ -222,17 +232,6 @@ sk_set_min_ttl4(sock *s, int ttl)
   return NULL;
 }
 
-#else /* no IP_MINTTL */
-
-static inline char *
-sk_set_min_ttl4(sock *s, int ttl)
-{
-  errno = ENOPROTOOPT;
-  return "IP_MINTTL";
-}
-
-#endif
-
 static inline char *
 sk_set_min_ttl6(sock *s, int ttl)
 {