diff --git a/tools/testing/selftests/net/forwarding/forwarding.config.sample b/tools/testing/selftests/net/forwarding/forwarding.config.sample
index e2adb533c8fcb..b802c14d29509 100644
--- a/tools/testing/selftests/net/forwarding/forwarding.config.sample
+++ b/tools/testing/selftests/net/forwarding/forwarding.config.sample
@@ -14,6 +14,9 @@ NETIFS[p6]=veth5
 NETIFS[p7]=veth6
 NETIFS[p8]=veth7
 
+# Port that does not have a cable connected.
+NETIF_NO_CABLE=eth8
+
 ##############################################################################
 # Defines