<HTML dir=ltr><HEAD><TITLE>Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself</TITLE>
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<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Hi Simon,</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>Many thanks,</FONT></DIV>
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<DIV><FONT face=Arial size=2><STRONG>Alberto Cuesta-Canada</STRONG></FONT></DIV></DIV>
<DIV><FONT face=Arial size=1>GaaS Team Lead</FONT></DIV>
<DIV><FONT face=Arial size=1>Excelian Ltd.</FONT></DIV>
<DIV><FONT face=Arial size=1>+44 (0) 7942633361</FONT></DIV></FONT></DIV></DIV>
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<FONT face=Tahoma size=2><B>From:</B> Simon Kelley [mailto:simon@thekelleys.org.uk]<BR><B>Sent:</B> Wed 17/02/2010 10:04<BR><B>To:</B> Alberto Cuesta-Canada<BR><B>Cc:</B> dnsmasq-discuss@lists.thekelleys.org.uk; Grid Support<BR><B>Subject:</B> Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself<BR></FONT><BR></DIV>
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<P><FONT size=2>It's not clear to me what is going on here. How does the pattern<BR>continue? Do you just see "forwarded query to 172.30.48.192" from now<BR>on until the server is restarted, or do you still see "query[A]...." and<BR>"query[PTR}...." lines?<BR><BR>Do queries which get pushed upstream continue to work? How about queries<BR>which should be answered locally?<BR><BR>What is 172.30.158.94? Is it running anything that may generate "odd"<BR>DNS queries? The holy grail would be to able prod that machine to<BR>reproduce this at will.<BR><BR>What sort of machine are you running dnsmasq on? Does it have a<BR>reasonable amount of spare storage so that you could tcpdump all traffic<BR>to/from port 53,UDP for offline analysis?<BR><BR><BR>Simon.<BR></FONT></P></DIV><BR>
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