[Nagiosplug-help] random DNS check

[Thomas Guyot-Sionnest]

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On 12/02/08 10:09 AM, Philipp Hübner wrote:
> Hi list,
> 
> I want to monitor the performance of our local DNS-Server.
> If I use check_dns it always checks the same domain which will be cached by our server.

If you check authoritative servers it should be fairly representative of
the performance of your DNS servers. If you'd rather like to have a
global view of what latency your users get around the world (which it
the only "better" monitoring I could think of for an authoritative DNS
server) you'll need a distributed service that usually comes as a paid
subscription (I know Gomez though I'm not sure if they can check just
the DNS, you can at the very least see the resolving time of an HTTP
query; maybe Keynote, and there's certainly others...).

> So I'm looking for a plugin that works similar to check_dns but checks valid random domains.
> Maybe I could develop an own plugin for this case, but I don't have the time to do that.

- From that sentence I'm understanding you're checking a recursive DNS
server (DNS cache). That's doesn't make much sense, especially if you
try looking for random domains! The time it will take will be dependent
of tiers networks and you'll be alerted for THEIR problem. The only
checks I'd recommend on such servers would be either your own domains
(you can set-up a special zone/entry with ultra-low TTL if you want to
force re-check) or one of the root servers (like "a.ROOT-SERVERS.NET.").
What you're really interested in is knowing that your DNS cache
responds. You can't really help if the internet is broken...

Thomas
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