diff --git a/sysdep/cf/README b/sysdep/cf/README
index a3442752..b278fc5a 100644
--- a/sysdep/cf/README
+++ b/sysdep/cf/README
@@ -8,6 +8,7 @@ CONFIG_ALL_TABLES_AT_ONCE	Kernel scanner wants to process all tables at once
 
 CONFIG_UNIX_IFACE	Use Unix interface scanner
 CONFIG_UNIX_SET		Use Unix route setting
+CONFIG_UNIX_DONTROUTE   Use setsockopts DONTROUTE (undef for *BSD)
 CONFIG_LINUX_SCAN	Use Linux /proc/net/route scanner
 
 CONFIG_ALL_MULTICAST	krt-iface: All devices support multicasting (i.e., ignore IFF_MULTICAST)
diff --git a/sysdep/cf/bsd.h b/sysdep/cf/bsd.h
index cfce773e..f1475064 100644
--- a/sysdep/cf/bsd.h
+++ b/sysdep/cf/bsd.h
@@ -12,6 +12,7 @@
 
 #undef CONFIG_UNIX_IFACE
 #undef CONFIG_UNIX_SET
+#undef CONFIG_UNIX_DONTROUTE
 
 #define CONFIG_ALL_MULTICAST
 #define CONFIG_UNNUM_MULTICAST
diff --git a/sysdep/cf/linux-20.h b/sysdep/cf/linux-20.h
index 5c6a2377..247f0f1d 100644
--- a/sysdep/cf/linux-20.h
+++ b/sysdep/cf/linux-20.h
@@ -12,6 +12,7 @@
 
 #define CONFIG_UNIX_IFACE
 #define CONFIG_UNIX_SET
+#define CONFIG_UNIX_DONTROUTE
 #define CONFIG_LINUX_SCAN
 
 #define CONFIG_LINUX_MC_MREQ_BIND
diff --git a/sysdep/cf/linux-21.h b/sysdep/cf/linux-21.h
index 17882c81..57ae7962 100644
--- a/sysdep/cf/linux-21.h
+++ b/sysdep/cf/linux-21.h
@@ -12,6 +12,7 @@
 
 #define CONFIG_UNIX_IFACE
 #define CONFIG_UNIX_SET
+#define CONFIG_UNIX_DONTROUTE
 #define CONFIG_LINUX_SCAN
 
 #define CONFIG_LINUX_MC_MREQN
diff --git a/sysdep/cf/linux-22.h b/sysdep/cf/linux-22.h
index 52a4681a..f3629433 100644
--- a/sysdep/cf/linux-22.h
+++ b/sysdep/cf/linux-22.h
@@ -12,6 +12,7 @@
 #define CONFIG_ALL_TABLES_AT_ONCE
 
 #define CONFIG_LINUX_MC_MREQN
+#define CONFIG_UNIX_DONTROUTE
 
 /*
 Link: sysdep/linux/netlink
diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index c3bd5f8c..070150f6 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -578,8 +578,10 @@ sk_setup(sock *s)
     WARN("IP_TOS");
   if (s->ttl >= 0 && setsockopt(fd, SOL_IP, IP_TTL, &s->ttl, sizeof(s->ttl)) < 0)
     ERR("IP_TTL");
-  //if (s->ttl == 1 && setsockopt(fd, SOL_SOCKET, SO_DONTROUTE, &one, sizeof(one)) < 0)
-  //  ERR("SO_DONTROUTE");
+#ifdef CONFIG_UNIX_DONTROUTE
+  if (s->ttl == 1 && setsockopt(fd, SOL_SOCKET, SO_DONTROUTE, &one, sizeof(one)) < 0)
+    ERR("SO_DONTROUTE");
+#endif 
 #endif
   err = NULL;
 bad: