Hi Christian, Wireshark shows standard dns replays, and that's why ping works sometimes. The only irregularity I see are icmp "port unreachable" packets, generated because nothing is listening on 10.0.0.2:53. but I think it's not the problem! Thanks for you help. Ibrahim From: chest...@dca.fee.unicamp.br Date: Thu, 25 Aug 2011 10:13:38 -0300 Subject: Re: [nox-dev] Adding DNS functionality to nox To: ibrahim.me...@alumnos.upm.es
Hi Ibrahim, I would try to trace back where the problem might be. As you pointed, this could be due to:- nox and my reply packet, - mininet, - linux caches dns. - ? For the first possibility, have you tried to capture the DNS traffic with wireshark to see if they are correctly decoded? -Christian On Thu, Aug 25, 2011 at 07:22, ibrahim mun <ibrahim.me...@alumnos.upm.es> wrote: Hi again, One last question in this thread :) , about weird dns functionality: In mininet I have a single switch (s1), 4 hosts (h2,h3,h4,h5) (10.0.0.2 -> 10.0.0.5) resolve.conf points to 10.0.0.2 as dns server, but actually nox catchs dns requests matching with dst port 53, builds the response packet and sends it to the asker with src ip 10.0.0.2. first, I restart /etc/init.d/nscd, then xterm h3 h3>> ping -c2 pc4 it works correctly for one time ==================================== = PING pc4 (10.0.0.4) 56(84) bytes of data. = 64 bytes from 10.0.0.4: icmp_seq=1 ttl=64 time=19.9 ms = 64 bytes from 10.0.0.4: icmp_seq=2 ttl=64 time=3.39 ms = = --- pc4 ping statistics --- = 2 packets transmitted, 2 received, 0% packet loss, time 1007ms = rtt min/avg/max/mdev = 3.391/11.660/19.929/8.269 ms ==================================== then, for 3 to 5 times, it gives ==================================== = ping: unknow host pc4 ==================================== Then it works again for one time. Observations: 1. host sends dns request at every ping, even those with unknow host 2. I changed TTL in the dns reply (the time to be cached) and it has no effect. I don't know where is the problem (nox and my reply packet, mininet, how linux caches dns).. Thanks, Ibrahim From: ibrahim.me...@alumnos.upm.es To: jam...@nau.edu CC: nox-dev@noxrepo.org Subject: RE: [nox-dev] Adding DNS functionality to nox Date: Fri, 19 Aug 2011 15:17:58 +0200 Hi murphy, Thank you very much, I stupidly thought that 0 is a special value which means *full packet* instead of *zero bytes*, I've Added flows for both src and dst ports with higher priorty than pyswitch rules and finally it responses :D thank you again! Ibrahim _______________________________________________ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev -- Christian
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