[Xymon] What does the 'dns' test do?

John Horne john.horne at plymouth.ac.uk
Sun Mar 10 22:17:37 CET 2019


Using the 4.3.28 Terabithia RPMs, can someone tell me what the 'dns' test
actually does?

We actually negate the test ('!dns'), and run a client-side dns test ('dnsr')
to check that resolution is working. As far as I remember the standard 'dns'
test checks that the client DNS service can resolve something. This will always
fail in our case as the client DNS service is always restricted to just the
local host. (No querying allowed from an external server.)

I'm trying to work out why most of our servers are taking less than a second -
giving a 'Server unavailable' reply, but others are taking around 20 seconds
for a 'Timeout' reply. I know why the timeout is 20 seconds, I'm just wondering
why it's not giving a 'Server unavailable' reply.



John Horne | Senior Operations Analyst | Technology and Information Services
University of Plymouth | Drake Circus | Plymouth | Devon | PL4 8AA | UK

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