diff --git a/traffic-control/manual/run-tcdemo-test.sh b/traffic-control/manual/run-tcdemo-test.sh
index cbcbab6263350d3e688bd116a45a8bfda972cc4a..31f24c2b94f7ec3435398fb4e56649c57524785d 100755
--- a/traffic-control/manual/run-tcdemo-test.sh
+++ b/traffic-control/manual/run-tcdemo-test.sh
@@ -31,7 +31,7 @@ test_tcdemo() {
     local ret server_pid port="9000"
 
     ## Setup ##
-    sudo $TCMMD --save-stats=$TCMMD_LOG.$tc.$background -i eth0 >> $TCMMD_LOG 2>&1 &
+    sudo $TCMMD --save-stats=$TCMMD_LOG.$tc.$background -i $NET_INTERFACE >> $TCMMD_LOG 2>&1 &
     TCMMD_PID=$!
     ROOT_PROC_KILL_LIST+=($TCMMD_PID)