http://www.digitarchy.com/anycast/phcd.tgz Will do pretty much what you want. My target was a HTTP based service rather than DNS. Modification for UDP health checks should be trivial. -ansh -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Gere geomag Sent: Thursday, November 11, 2004 3:03 PM To: nanog@merit.edu Subject: Probe dns service - anycast network Hi, 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? Best regards Antony Findanno