diff --git a/sysdep/bsd/krt-sock.c b/sysdep/bsd/krt-sock.c
index d13e20a3..e8e555af 100644
--- a/sysdep/bsd/krt-sock.c
+++ b/sysdep/bsd/krt-sock.c
@@ -394,30 +394,6 @@ krt_replace_rte(struct krt_proto *p, net *n UNUSED, rte *new, rte *old)
   }
 }
 
-/**
- * krt_assume_onlink - check if routes on interface are considered onlink
- * @iface: The interface of the next hop
- * @ipv6: Switch to only consider IPv6 or IPv4 addresses.
- *
- * The BSD kernel does not support an onlink flag. If the interface has only
- * host addresses configured, all routes should be considered as onlink and
- * the function returns 1.
- */
-static int
-krt_assume_onlink(struct iface *iface, int ipv6)
-{
-  const u8 type = ipv6 ? NET_IP6 : NET_IP4;
-
-  struct ifa *ifa;
-  WALK_LIST(ifa, iface->addrs)
-  {
-    if ((ifa->prefix.type == type) && !(ifa->flags & IA_HOST))
-      return 0;
-  }
-
-  return 1;
-}
-
 #define SKIP(ARG...) do { DBG("KRT: Ignoring route - " ARG); return; } while(0)
 
 static void
diff --git a/sysdep/cf/README b/sysdep/cf/README
index af65aaec..cdaf5da1 100644
--- a/sysdep/cf/README
+++ b/sysdep/cf/README
@@ -5,6 +5,7 @@ CONFIG_AUTO_ROUTES	Device routes are added automagically by the kernel
 CONFIG_SELF_CONSCIOUS	We're able to recognize whether route was installed by us
 CONFIG_MULTIPLE_TABLES	The kernel supports multiple routing tables
 CONFIG_SINGLE_ROUTE	There is only one route per network
+CONFIG_ASSUME_ONLINK	Assume ONLINK flag on scanned routes based on a heuristic
 
 CONFIG_MC_PROPER_SRC	Multicast packets have source address according to socket saddr field
 CONFIG_SKIP_MC_BIND	Don't call bind on multicast socket (def for *BSD)
diff --git a/sysdep/cf/bsd-netlink.h b/sysdep/cf/bsd-netlink.h
index 69297867..a65106a3 100644
--- a/sysdep/cf/bsd-netlink.h
+++ b/sysdep/cf/bsd-netlink.h
@@ -10,6 +10,7 @@
 #define CONFIG_SELF_CONSCIOUS
 #define CONFIG_MULTIPLE_TABLES
 #define CONFIG_SINGLE_ROUTE
+#define CONFIG_ASSUME_ONLINK
 
 #define CONFIG_SKIP_MC_BIND
 #define CONFIG_NO_IFACE_BIND
diff --git a/sysdep/cf/bsd.h b/sysdep/cf/bsd.h
index 22c54277..56ba0a1a 100644
--- a/sysdep/cf/bsd.h
+++ b/sysdep/cf/bsd.h
@@ -10,6 +10,7 @@
 #define CONFIG_SELF_CONSCIOUS
 #define CONFIG_MULTIPLE_TABLES
 #define CONFIG_SINGLE_ROUTE
+#define CONFIG_ASSUME_ONLINK
 
 #define CONFIG_SKIP_MC_BIND
 #define CONFIG_NO_IFACE_BIND
diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c
index 533cc268..299f132f 100644
--- a/sysdep/linux/netlink.c
+++ b/sysdep/linux/netlink.c
@@ -788,6 +788,11 @@ nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, const net_addr
 
       if (ipa_nonzero(rv->gw))
 	{
+#ifdef CONFIG_ASSUME_ONLINK
+	  if (krt_assume_onlink(rv->iface, ipa_is_ip6(rv->gw)))
+	    rv->flags |= RNF_ONLINK;
+#endif
+
 	  neighbor *nbr;
 	  nbr = neigh_find(&p->p, rv->gw, rv->iface,
 			   (rv->flags & RNF_ONLINK) ? NEF_ONLINK : 0);
@@ -1739,6 +1744,11 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
 	  if ((i->rtm_family == AF_INET6) && ipa_in_netX(ra->nh.gw, (net_addr *) &sit))
 	    return;
 
+#ifdef CONFIG_ASSUME_ONLINK
+	  if (krt_assume_onlink(ra->nh.iface, ipa_is_ip6(ra->nh.gw)))
+	    ra->nh.flags |= RNF_ONLINK;
+#endif
+
 	  neighbor *nbr;
 	  nbr = neigh_find(&p->p, ra->nh.gw, ra->nh.iface,
 			   (ra->nh.flags & RNF_ONLINK) ? NEF_ONLINK : 0);
diff --git a/sysdep/unix/krt.c b/sysdep/unix/krt.c
index 51d0718c..5baaf18b 100644
--- a/sysdep/unix/krt.c
+++ b/sysdep/unix/krt.c
@@ -909,6 +909,30 @@ krt_scan_timer_kick(struct krt_proto *p)
     tm_start(p->scan_timer, 0);
 }
 
+/**
+ * krt_assume_onlink - check if routes on interface are considered onlink
+ * @iface: The interface of the next hop
+ * @ipv6: Switch to only consider IPv6 or IPv4 addresses.
+ *
+ * The BSD kernel does not support an onlink flag. If the interface has only
+ * host addresses configured, all routes should be considered as onlink and
+ * the function returns 1. This is used when CONFIG_ASSUME_ONLINK is set.
+ */
+int
+krt_assume_onlink(struct iface *iface, int ipv6)
+{
+  const u8 type = ipv6 ? NET_IP6 : NET_IP4;
+
+  struct ifa *ifa;
+  WALK_LIST(ifa, iface->addrs)
+  {
+    if ((ifa->prefix.type == type) && !(ifa->flags & IA_HOST))
+      return 0;
+  }
+
+  return 1;
+}
+
 
 /*
  *	Updates
diff --git a/sysdep/unix/krt.h b/sysdep/unix/krt.h
index e25f0b12..2b1dfa96 100644
--- a/sysdep/unix/krt.h
+++ b/sysdep/unix/krt.h
@@ -83,6 +83,7 @@ void kif_request_scan(void);
 void krt_use_shared_scan(void);
 void krt_got_route(struct krt_proto *p, struct rte *e, s8 src);
 void krt_got_route_async(struct krt_proto *p, struct rte *e, int new, s8 src);
+int krt_assume_onlink(struct iface *iface, int ipv6);
 
 static inline int
 krt_get_sync_error(struct krt_proto *p, struct rte *e)