[dns-operations] Distributed Monitoring

[Brett]

For various reasons we are currently considering changing some of the
monitoring around our DNS platform. We are specifically looking at the
distributed monitoring of Anycast  Auth DNS servers (IE from multiple
end points). I was wondering what other people use for this type of
monitoring? Anything you would strongly recommend or strongly advise
against. Open source along with commercial and SAAS solutions would
all be considered, the most important things are reliability and cost.

Thanks.

-- 
Brett