On 11 Nov 2004, at 18:02, Gere geomag wrote:

We are thinking of deploying anycast in our network for dns servers. I have the following scenario: - 10 server DNS (isc-bind) , linux and zebra for propagating ospf ip anycast.

Are there someone who has developed a "solid scripts (perl/c/ecc..)" that is used to probe a dns service (udp/tcp port 53) and in case of failure (or max lookup query time problem) automatic shutdown ospf annunce or remove a server from a anycast network?

This doesn't quite answer your question, but there's a wrapper script here: http://www.isc.org/pubs/tn/isc-tn-2004-1.html#appx.WrapperScript which kind of does what you're asking. It relies on BIND 9 dumping core upon experiencing an assertion failure (or any kind of failure which is likely to cause it to fail). BIND 9 is quite good at dumping core when it gets confused (by design, in case anybody thinks I'm being sarcastic). You could always augment that with a crob job which does some digs, and creates ${stop_file} and kills named in the event that the digs fail. Testing remotely may also be a good idea. There are allusions made in: http://www.ietf.org/internet-drafts/draft-kurtis-anycast-bcp-00.txt to some of the monitoring and measurement issues surrounding anycast service deployments. In any case, there are many ways to skin this cat. Joe