[Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
alberto.cuesta at excelian.com
Wed Feb 17 10:22:31 GMT 2010
the parents of 250 (my dnsmasq server) have forwarding rules for the dselgrid.local domain, that I run. So I assumed that the queries pushed upstream would be routed down again, and timeout in a loop.
That said, in the logs I could still see successful PTR and A queries, outnumbered 10 to 1 by forwards. I'm not sure about the behaviour of local queries, I don't remember from yesterday, but I think they worked.
94 is a Platform Grid Master, that is a W2K3 machine which runs only one application. It keeps a cache of machines but it doesn't give DNS services, or anything similar. The interesting thing is that the PTR request doesn't always produce this effect. I have enterprise support for that software, so I will ask them.
dnsmasq is running in a quite complicated setup. We have a XenServer host running a Ubuntu 9.04 VM. I have just 1GB free on that machine and out of disk space scenarios are fatal, so I can't tcpdump. There is a rebuild of it coming in the next two weeks that will give me another 50GB.
Any idea on what to look for, or any hypothesis of what could be happening should be enough, I can keep investigating and contain it with workarounds for a while.
GaaS Team Lead
+44 (0) 7942633361
From: Simon Kelley [mailto:simon at thekelleys.org.uk]
Sent: Wed 17/02/2010 10:04
To: Alberto Cuesta-Canada
Cc: dnsmasq-discuss at lists.thekelleys.org.uk; Grid Support
Subject: Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
It's not clear to me what is going on here. How does the pattern
continue? Do you just see "forwarded query to 172.30.48.192" from now
on until the server is restarted, or do you still see "query[A]...." and
Do queries which get pushed upstream continue to work? How about queries
which should be answered locally?
What is 172.30.158.94? Is it running anything that may generate "odd"
DNS queries? The holy grail would be to able prod that machine to
reproduce this at will.
What sort of machine are you running dnsmasq on? Does it have a
reasonable amount of spare storage so that you could tcpdump all traffic
to/from port 53,UDP for offline analysis?
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