last night we had an issue with one of our servers, basically I have 2 core switches using vrrp, we have remote sites that come into the office, this traffic then hits the core switches, then to the server. what was happening is that everything on the lan locally on the core seems ok on the active router, but the wan traffic comes into the backup master router. The server is a cluster and has an alias address, from the wan we can ping the real addresses but not the alias, but from the lans locally it seems fine. One thing I noticed is that the alias arp entry was missing from one of the core routers, the one where it comes in from the wan.
The only way I got it working was to run a ping from the core switch to the server, this then put the arp entry back in the cache. but when I ping from the wan its almost like its not arping!!
any ideas why this is happening ?