Ethereal-dev: Re: [Ethereal-dev] TCP/IP Retransmission

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

From: Stephen Samuel <samuel@xxxxxxxxxxx>
Date: Mon, 22 Mar 2004 09:35:03 -0800
I once used a combination of ethereal, mtr and multiple
repeating wget loops to track the problem to a specific
overloaded router hop.  It's a bit hairy, but it is doable.


Ian Schorr wrote:
.....
Use this technique to prove to them - try to arrange to have captures taken simultaneously on both sides of the link that you suspect is faulty. Find a retransmission event, and figure out what happened - was the packet actually "lost" on the link? If so, you should be able to find the original copy of a retransmitted segment sent out to the SP's link AS WELL as the retransmitted segment (and in such a trace even Sniffer *should* find the retransmission), but when you look at the trace on the other side of the link, that original segment should be gone. Ask them where the packet went?

Ian

Chula Bandara wrote:

Hi i am using Etereal Version 0.10.0a and this was very useful to me solving connectivity issues with our Service Providers. Few days back i had a similar problem that i see TCP retransmission but one of my Service Provider did not those retransmissions. My SP was using Network Associates Sniffer Pro Version 4.50.04. and i got some of captured files from the Sniffer. Surprisingly when i open those files with Ethereal , it sees Retransmissions , Packet Losses , Duplicate ACks etc..

could this be a bug in Ethereal or the Sniffer
thanks you in advance.
cbandara


--
Stephen Samuel +1(604)876-0426                samuel@xxxxxxxxxxx
		   http://www.bcgreen.com/~samuel/
   Powerful committed communication. Transformation touching
     the jewel within each person and bringing it to light.