Wireshark-users: Re: [Wireshark-users] TCP retransmit, HTTP and web page not loading
From: Sake Blok <[email protected]>
Date: Wed, 25 Jun 2008 17:18:17 +0200
On Wed, Jun 25, 2008 at 10:38:09AM -0400, Steve Bertrand wrote:
> Sake Blok wrote:
> > On Wed, Jun 25, 2008 at 09:19:46AM -0400, Steve Bertrand wrote:
> >> There is a screen cap of the final communication between the server and 
> >> client if anyone could possibly have a look if they can answer my questions.
> >>
> >> http://ibctech.ca/screencap/fibre_communication.jpg
> > 
> > Please provide the (binary) capture file instead of a screendump. We love
> > using wireshark instead of an image-viewer ;-)
> LOL, sorry. Like I said, new to list, and no charter or BCP ;)

Hmmm... it might be a good idea indeed to have a charter... :-)

> That said, I certainly should have known better.
> I hope this is what you are after. I'm not all that familiar with 
> Wireshark, as I do all of my traces via tcpdump on FreeBSD. I just saved 
> a new file from within Wireshark with the packets from the entire HTTP 
> conversation in question:
> http://ibctech.ca/http-conv.pcap

Yep, that's exactly what I was after!

In the trace you can see (by using "follow tcp stream" on one of the
retransmissions) that there is actually no response from the server.
This means the problem lies between the capturing device and the server
(either the request gets lost or the response gets lost). Since the
fibre is on the 'other' side of your capturing device, you can assume
the fibre is not causing the packet loss. However, since doing the
same test on the other side of the link does not show the problem, the
question is how are the two different.

Do you also have the capture of the same laptop going to the
site from the other side of the fibre?

> Since I've had to delve into this the last couple days, I'm going to go 
> off on a tangent to learn much more about this level of network 
> communication.

Well, buckle up and enjoy the (rough) ride ;-)