Server stopped DNS name resolution

[Lev Olshvang]

Try wireshark/tcpdump  to see which DNS queries goes to which server and  wheter DNS server replies back .

You can also try dig, nslookup and couple of other cmoomd line tools form:

http://serverfault.com/questions/7056/whats-the-reverse-dns-command-line-utility/7088#7088


From: Linux-il [mailto:linux-il-bounces at cs.huji.ac.il] On Behalf Of Gabor Szabo
Sent: Sunday, March 22, 2015 1:14 PM
To: guy keren
Cc: linux-il
Subject: Re: Server stopped DNS name resolution

I tried that, and although I am not sure what should I look for in there it seems to be claiming

rt_sigsuspend([];; connection timed out; no servers could be reached

I tried to telnet 72.14.179.5 53  (one of the DNS servers) and that did not got a response.

Anyway, Linode support told me to add this to the resolve.conf
nameserver 8.8.8.8
nameserver 8.8.4.4

and that seemed to do the trick.

Gabor

On Sun, Mar 22, 2015 at 1:00 PM, guy keren <guy.choo.keren at gmail.com<mailto:guy.choo.keren at gmail.com>> wrote:

run this on the host:

strace host www.google.com<http://www.google.com>

and scan the output.

more efficient then guessing.

--guy

On 03/22/2015 12:50 PM, Gabor Szabo wrote:
Hi,

I run an Ubuntu based VPS on Linode.
I few hours ago the machine stopped resolving hostnames.
I think it was after an "aptitude safe-upgrade" and a reboot, but I am
not sure. Maybe was like this earlier.

It takes ages to ssh to it, once I got to the machine I can ping IP
addresses from it, but I cannot ping anything with a hostname.

this is what I have in resolv.conf

# cat /etc/resolv.conf

domain members.linode.com<http://members.linode.com> <http://members.linode.com>

search members.linode.com<http://members.linode.com> <http://members.linode.com>

nameserver 72.14.179.5

nameserver 72.14.188.5

options rotate


I tried to replace the nameservers with others that are listed in
another of my servers, but that did not make a change.

How can I track down what has the server stopped resolving hostnames?

Accessing the server via HTTP work as expected.

Gabor

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