I often get reqquest to flush our DNS cache from various folks withing
our department. The most recent incident was when they suspected
another ISP had it's domains hijacked and they didn't want it
posioning our caches, mind you they couldn't tell me the name of the
offending domains so I could at least see if they were posioned or not
on our network.

So anyways I'm just wondering do others find the need to flush thier
caching servers regularly or at all, or do you just leave it until it
becomes FIFO kind of thing.

Thanks.