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.