nanog mailing list archives

Re: Reliable Cloud host ?


From: Randy Carpenter <rcarpen () network1 net>
Date: Mon, 27 Feb 2012 12:36:00 -0500 (EST)


Pardon the weird question:

Is the DNS service authoritative or recursive?  If auth, you can
solve this a few ways, either by giving the DNS name people point to
multiple AAAA (and A) records pointing at a diverse set of
instances.

Authoritative. But, also not the only thing that we are running that needs some geographic and route diversity.

DNS is designed to work around a host being down.  Same
goes for MX and several other services.  While it may make the
service slightly slower, it's certainly not the end of the world.

Oh, how I wish this were true in practice. If I had a dollar for every time we had serious issues because one of a few 
authoritative DNS servers was not responding... OK, I wouldn't be rich, but this happens all the time. Caching servers 
out on the net get a "non-answer" because the server they chose to ask was down, and it caches that. They shouldn't do 
that, but they do, and there's nothing that can be done about it.

-Randy


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