[Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
Hi guys, I saw a weird scenario in one of our dnsmasq servers yesterday. As the logs below show, the server was all happy doing its thing, until a set of PTR queries came from normal servers in our network. The last of it would ask for the hostname of the dns server giving the IP, and from that point dnsmasq would route all traffic to the parents. Restarting the dnsmasq service would restore the server to normal operations. This has happened 4 times in the last 10 days, always with the same pattern. Feb 17 01:35:51 dnsmasq[28538]: query[A] grdvpm3.dselgrid.local from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts grdvpm3.dselgrid.local is 172.30.158.93 Feb 17 01:35:51 dnsmasq[28538]: query[PTR] 93.158.30.172.in-addr.arpa from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts 172.30.158.93 is grdvpm3.dselgrid.local Feb 17 01:35:51 dnsmasq[28538]: query[A] grdvpm3.dselgrid.local from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts grdvpm3.dselgrid.local is 172.30.158.93 Feb 17 01:37:16 dnsmasq[28538]: query[MX] smtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded smtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: query[MX] vsmtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded vsmtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: query[A] smtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded smtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: reply smtpmail.daiwaeurope.local is CNAME Feb 17 01:37:16 dnsmasq[28538]: reply vsmtpmail.daiwaeurope.local is 172.30.19.221 Feb 17 01:37:52 dnsmasq[28538]: query[PTR] 250.158.30.172.in-addr.arpa from 172.30.158.94 Feb 17 01:37:52 dnsmasq[28538]: /etc/hosts 172.30.158.250 is grdxk-mgmt1.dselgrid.local Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Any idea what would be going on? Is that PTR query a signal that some other service could be asking the DNS server to stop reading the hosts file? Many thanks, Alberto Cuesta-Canada GaaS Team Lead Excelian Ltd. +44 (0) 7942633361 The information contained in this email and any attached files are confidential and intended solely for the addressee(s). The email may be legally privileged or prohibited from disclosure and unauthorised use. If you are not the named addressee you may not use, copy, or disclose this information to any other person. If you received this message in error please notify the sender immediately and delete it from your system. Any opinion or views contained in this email message are those of the sender, and do not represent those of the Company in any way and reliance should not be placed upon its contents. Unless otherwise stated, this email message is not intended to be contractually binding. Where an Agreement exists between our respective companies and there is conflict between the contents of this email message and the Agreement then the terms of that Agreement shall prevail. Excelian 50 Featherstone Street London EC1Y 8RT Tel: +44 (0) 20 7336 9595 Fax: +44 (0) 20 7336 9596 www.Excelian.com _ This e-mail has been scanned for viruses by MessageLabs. For further information visit http://www.messagelabs.com Excelian subscribes to cleaner and greener methods of working. Help take responsibility for the environment. Please don't print this email unless you absolutely have to.
Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
Alberto Cuesta-Canada wrote: Hi guys, I saw a weird scenario in one of our dnsmasq servers yesterday. As the logs below show, the server was all happy doing its thing, until a set of PTR queries came from normal servers in our network. The last of it would ask for the hostname of the dns server giving the IP, and from that point dnsmasq would route all traffic to the parents. Restarting the dnsmasq service would restore the server to normal operations. This has happened 4 times in the last 10 days, always with the same pattern. Feb 17 01:35:51 dnsmasq[28538]: query[A] grdvpm3.dselgrid.local from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts grdvpm3.dselgrid.local is 172.30.158.93 Feb 17 01:35:51 dnsmasq[28538]: query[PTR] 93.158.30.172.in-addr.arpa from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts 172.30.158.93 is grdvpm3.dselgrid.local Feb 17 01:35:51 dnsmasq[28538]: query[A] grdvpm3.dselgrid.local from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts grdvpm3.dselgrid.local is 172.30.158.93 Feb 17 01:37:16 dnsmasq[28538]: query[MX] smtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded smtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: query[MX] vsmtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded vsmtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: query[A] smtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded smtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: reply smtpmail.daiwaeurope.local is CNAME Feb 17 01:37:16 dnsmasq[28538]: reply vsmtpmail.daiwaeurope.local is 172.30.19.221 Feb 17 01:37:52 dnsmasq[28538]: query[PTR] 250.158.30.172.in-addr.arpa from 172.30.158.94 Feb 17 01:37:52 dnsmasq[28538]: /etc/hosts 172.30.158.250 is grdxk-mgmt1.dselgrid.local Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Any idea what would be going on? Is that PTR query a signal that some other service could be asking the DNS server to stop reading the hosts file? Which version of dnsmasq are you using? Simon.
Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
Hi Simon, 2.47 Cheers, Alberto Cuesta-Canada GaaS Team Lead Excelian Ltd. +44 (0) 7942633361 From: Simon Kelley [mailto:si...@thekelleys.org.uk] Sent: Wed 17/02/2010 09:46 To: Alberto Cuesta-Canada Cc: dnsmasq-discuss@lists.thekelleys.org.uk; Grid Support Subject: Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself Alberto Cuesta-Canada wrote: Hi guys, I saw a weird scenario in one of our dnsmasq servers yesterday. As the logs below show, the server was all happy doing its thing, until a set of PTR queries came from normal servers in our network. The last of it would ask for the hostname of the dns server giving the IP, and from that point dnsmasq would route all traffic to the parents. Restarting the dnsmasq service would restore the server to normal operations. This has happened 4 times in the last 10 days, always with the same pattern. Feb 17 01:35:51 dnsmasq[28538]: query[A] grdvpm3.dselgrid.local from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts grdvpm3.dselgrid.local is 172.30.158.93 Feb 17 01:35:51 dnsmasq[28538]: query[PTR] 93.158.30.172.in-addr.arpa from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts 172.30.158.93 is grdvpm3.dselgrid.local Feb 17 01:35:51 dnsmasq[28538]: query[A] grdvpm3.dselgrid.local from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts grdvpm3.dselgrid.local is 172.30.158.93 Feb 17 01:37:16 dnsmasq[28538]: query[MX] smtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded smtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: query[MX] vsmtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded vsmtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: query[A] smtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded smtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: reply smtpmail.daiwaeurope.local is CNAME Feb 17 01:37:16 dnsmasq[28538]: reply vsmtpmail.daiwaeurope.local is 172.30.19.221 Feb 17 01:37:52 dnsmasq[28538]: query[PTR] 250.158.30.172.in-addr.arpa from 172.30.158.94 Feb 17 01:37:52 dnsmasq[28538]: /etc/hosts 172.30.158.250 is grdxk-mgmt1.dselgrid.local Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Any idea what would be going on? Is that PTR query a signal that some other service could be asking the DNS server to stop reading the hosts file? Which version of dnsmasq are you using? Simon. The information contained in this email and any attached files are confidential and intended solely for the addressee(s). The email may be legally privileged or prohibited from disclosure and unauthorised use. If you are not the named addressee you may not use, copy, or disclose this information to any other person. If you received this message in error please notify the sender immediately and delete it from your system. Any opinion or views contained in this email message are those of the sender, and do not represent those of the Company in any way and reliance should not be placed upon its contents. Unless otherwise stated, this email message is not intended to be contractually binding. Where an Agreement exists between our respective companies and there is conflict between the contents of this email message and the Agreement then the terms of that Agreement shall prevail. Excelian 50 Featherstone Street London EC1Y 8RT Tel: +44 (0) 20 7336 9595 Fax: +44 (0) 20 7336 9596 www.Excelian.com _ This e-mail has been scanned for viruses by MessageLabs. For further information visit http://www.messagelabs.com Excelian subscribes to cleaner and greener methods of working. Help take responsibility for the environment. Please don't print this email unless you absolutely have to.
Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
Alberto Cuesta-Canada wrote: Hi guys, I saw a weird scenario in one of our dnsmasq servers yesterday. As the logs below show, the server was all happy doing its thing, until a set of PTR queries came from normal servers in our network. The last of it would ask for the hostname of the dns server giving the IP, and from that point dnsmasq would route all traffic to the parents. Restarting the dnsmasq service would restore the server to normal operations. This has happened 4 times in the last 10 days, always with the same pattern. Feb 17 01:35:51 dnsmasq[28538]: query[A] grdvpm3.dselgrid.local from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts grdvpm3.dselgrid.local is 172.30.158.93 Feb 17 01:35:51 dnsmasq[28538]: query[PTR] 93.158.30.172.in-addr.arpa from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts 172.30.158.93 is grdvpm3.dselgrid.local Feb 17 01:35:51 dnsmasq[28538]: query[A] grdvpm3.dselgrid.local from 172.30.158.98 Feb 17 01:35:51 dnsmasq[28538]: /etc/hosts grdvpm3.dselgrid.local is 172.30.158.93 Feb 17 01:37:16 dnsmasq[28538]: query[MX] smtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded smtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: query[MX] vsmtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded vsmtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: query[A] smtpmail.daiwaeurope.local from 127.0.0.1 Feb 17 01:37:16 dnsmasq[28538]: forwarded smtpmail.daiwaeurope.local to 172.30.48.192 Feb 17 01:37:16 dnsmasq[28538]: reply smtpmail.daiwaeurope.local is CNAME Feb 17 01:37:16 dnsmasq[28538]: reply vsmtpmail.daiwaeurope.local is 172.30.19.221 Feb 17 01:37:52 dnsmasq[28538]: query[PTR] 250.158.30.172.in-addr.arpa from 172.30.158.94 Feb 17 01:37:52 dnsmasq[28538]: /etc/hosts 172.30.158.250 is grdxk-mgmt1.dselgrid.local Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Feb 17 01:37:52 dnsmasq[28538]: forwarded query to 172.30.48.192 Any idea what would be going on? Is that PTR query a signal that some other service could be asking the DNS server to stop reading the hosts file? 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 query[PTR} lines? 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? Simon.
Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
Hi Simon, 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. Many thanks, Alberto Cuesta-Canada GaaS Team Lead Excelian Ltd. +44 (0) 7942633361 From: Simon Kelley [mailto:si...@thekelleys.org.uk] Sent: Wed 17/02/2010 10:04 To: Alberto Cuesta-Canada Cc: dnsmasq-discuss@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 query[PTR} lines? 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? Simon. The information contained in this email and any attached files are confidential and intended solely for the addressee(s). The email may be legally privileged or prohibited from disclosure and unauthorised use. If you are not the named addressee you may not use, copy, or disclose this information to any other person. If you received this message in error please notify the sender immediately and delete it from your system. Any opinion or views contained in this email message are those of the sender, and do not represent those of the Company in any way and reliance should not be placed upon its contents. Unless otherwise stated, this email message is not intended to be contractually binding. Where an Agreement exists between our respective companies and there is conflict between the contents of this email message and the Agreement then the terms of that Agreement shall prevail. Excelian 50 Featherstone Street London EC1Y 8RT Tel: +44 (0) 20 7336 9595 Fax: +44 (0) 20 7336 9596 www.Excelian.com _ This e-mail has been scanned for viruses by MessageLabs. For further information visit http://www.messagelabs.com Excelian subscribes to cleaner and greener methods of working. Help take responsibility for the environment. Please don't print this email unless you absolutely have to.
Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
Alberto Cuesta-Canada wrote: Hi Simon, 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. Ahh, that could easily be the problem. If you generate a loop between two DNS servers, each forwarding to the other, then the queries can easily bounce back-and-forth forever. Dnsmasq will manage this situation reasonably well, and manage to server other traffic, but the circulating queries will eat bandwidth and CPU. The logs would seem to show a strange query of some sort (dnsmasq can't parse a domain-name from the query, hence forwarded query rather than forwarded domain-name) If such queries can circulate forever then you have a problem. 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. See above. a loop, possibly only of odd queries. Cheers, Simon. Many thanks, *Alberto Cuesta-Canada* GaaS Team Lead Excelian Ltd. +44 (0) 7942633361 *From:* Simon Kelley [mailto:si...@thekelleys.org.uk] *Sent:* Wed 17/02/2010 10:04 *To:* Alberto Cuesta-Canada *Cc:* dnsmasq-discuss@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 query[PTR} lines? 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? Simon. The information contained in this email and any attached files are confidential and intended solely for the addressee(s). The email may be legally privileged or prohibited from disclosure and unauthorised use. If you are not the named addressee you may not use, copy, or disclose this information to any other person. If you received this message in error please notify the sender immediately and delete it from your system. Any opinion or views contained in this email message are those of the sender, and do not represent those of the Company in any way and reliance should not be placed upon its contents. Unless otherwise stated, this email message is not intended to be contractually binding. Where an Agreement exists between our respective companies and there is conflict between the contents of this email message and the Agreement then the terms of that Agreement shall prevail. Excelian 50 Featherstone Street London EC1Y 8RT Tel: +44 (0) 20 7336 9595 Fax: +44 (0) 20 7336 9596 www.Excelian.com _ This e-mail has been scanned for viruses by MessageLabs. For further information visit http://www.messagelabs.com Excelian subscribes to cleaner and greener methods of working. Help take responsibility for the environment. Please don't print this email unless you absolutely have to.
Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself
Cool, that makes a lot of sense. I'm actually reengineering the DNS infrastructure here, so it will be easy to account for and trace that at this stage. I'll let you know when I find the rogue queries, many thanks, Alberto Cuesta-Canada GaaS Team Lead Excelian Ltd. +44 (0) 7942633361 From: Simon Kelley [mailto:si...@thekelleys.org.uk] Sent: Wed 17/02/2010 10:30 To: Alberto Cuesta-Canada Cc: dnsmasq-discuss@lists.thekelleys.org.uk; Grid Support Subject: Re: [Dnsmasq-discuss] server forwarding all traffic to parents after a successful PTR query of itself Alberto Cuesta-Canada wrote: Hi Simon, 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. Ahh, that could easily be the problem. If you generate a loop between two DNS servers, each forwarding to the other, then the queries can easily bounce back-and-forth forever. Dnsmasq will manage this situation reasonably well, and manage to server other traffic, but the circulating queries will eat bandwidth and CPU. The logs would seem to show a strange query of some sort (dnsmasq can't parse a domain-name from the query, hence forwarded query rather than forwarded domain-name) If such queries can circulate forever then you have a problem. 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. See above. a loop, possibly only of odd queries. Cheers, Simon. Many thanks, *Alberto Cuesta-Canada* GaaS Team Lead Excelian Ltd. +44 (0) 7942633361 *From:* Simon Kelley [mailto:si...@thekelleys.org.uk] *Sent:* Wed 17/02/2010 10:04 *To:* Alberto Cuesta-Canada *Cc:* dnsmasq-discuss@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 query[PTR} lines? 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? Simon. The information contained in this email and any attached files are confidential and intended solely for the addressee(s). The email may be legally privileged or prohibited from disclosure and unauthorised use. If you are not the named addressee you may not use, copy, or disclose this information to any other person. If you received this message in error please notify the sender immediately and delete it from your system. Any opinion or views contained in this email message are those of the sender, and do not represent those of the Company in any way and reliance should not be placed upon its contents. Unless otherwise stated, this email message is not intended to be contractually binding. Where an Agreement exists between our respective companies and there is conflict between the contents of this email message and the Agreement then the terms of that Agreement shall prevail. Excelian 50 Featherstone Street London EC1Y 8RT Tel: +44 (0) 20 7336 9595 Fax: +44 (0) 20 7336 9596 www.Excelian.com _ This e-mail has been scanned for viruses by MessageLabs. For further information visit http://www.messagelabs.com http://www.messagelabs.com/ Excelian subscribes to cleaner and greener methods of working. Help take responsibility for the environment. Please don't
