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                                           
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