diff --git a/README.md b/README.md
index 30b3f36..e5b28de 100644
--- a/README.md
+++ b/README.md
@@ -34,7 +34,7 @@ Open `/usr/local/etc/lxc-iptag.conf` and change the config
 | ------------------------------- | ------------------------------------------- | ------------------------------------------------------------------------------------------------------- |
 | CIDR_LIST                       | `(192.168.0.0/16 100.64.0.0/10 10.0.0.0/8)` | IP filter list in CIDR format                                                                           |
 | LOOP_INTERVAL                   | `60`                                        | Main loop interval(seconds)                                                                             |
-| FW_NET_INTERFACE_CHECK_INTERVAL | `60`                                        | The interval(seconds) for using `ifconfig` to check lxc status changed (Set -1 to disable this feature) |
+| FW_NET_INTERFACE_CHECK_INTERVAL | `60`                                        | The interval(seconds) for using `ip link` to check lxc status changed (Set -1 to disable this feature) |
 | LXC_STATUS_CHECK_INTERVAL       | `-1`                                        | The interval(seconds) for using `pct list` to check lxc status changed (Set -1 to disable this feature) |
 | FORCE_UPDATE_INTERVAL           | `1800`                                      | The interval(seconds) for force check and update lxc tags                                               |
 
diff --git a/lxc-iptag b/lxc-iptag
index 5e03a0c..1d0ce48 100755
--- a/lxc-iptag
+++ b/lxc-iptag
@@ -82,7 +82,7 @@ lxc_status_changed() {
 }
 
 fw_net_interface_changed() {
-    current_net_interface=$(ip link | grep fw)
+    current_net_interface=$(ip link | grep "^[0-9]*: fw")
     if [ "${last_net_interface}" == "${current_net_interface}" ]; then
         return 1
     else