I run a Linux server in a subnet that is not under my control. From time to time, the server can not be reached from outside (the Internet) for a few seconds. I'm trying to trace why and started to have a look on the output of `ip neigh show` (written out to a file regularly with a cron job).

The next time it happened I looked at the file, and it read:

```
fe80::1 dev eth0 lladdr 00:22:64:b6:10:5c router STALE
192.168.14.1 dev eth0  FAILED

```

For me, this looks like the gateway (which is 192.168.14.1) does not respond on ARP requests made by the server. Is this correct?

I was trying to find more information, particularly in the `iproute2` source code, but didn't find under which condition it would write out FAILED. But maybe that's because I'm not a C developer.