diff --git a/src/opt/babeld-monitor/babeld-monitor.sh b/src/opt/babeld-monitor/babeld-monitor.sh
index e9a3964..b94c7eb 100755
--- a/src/opt/babeld-monitor/babeld-monitor.sh
+++ b/src/opt/babeld-monitor/babeld-monitor.sh
@@ -39,7 +39,7 @@ else
     
     # add tunnel interfaces to babeld
     echo "add tunnel interfaces to babeld..."
-    ip addr | tr ' ' '\n' | grep -E "l2tp[0-9]+$" | sort | uniq | xargs -L 1 babeld -a 
+    ip addr | tr ' ' '\n' | grep -E "l2tp[0-9\-]+$" | sort | uniq | xargs -L 1 babeld -a 
     babeld -i | head -n1
     echo "add tunnel interfaces to babeld done."