Wireshark-users: [Wireshark-users] Understanding what I'm seeing

From: Chad Webb <Chad.Webb@xxxxxxxx>
Date: Wed, 10 Oct 2007 08:20:00 -0500

I'm currently using version 0.99.6 on a Windows platform.

I have the following configuration set up on my Cisco 3560 switch.

monitor session 1 source interface Gi0/21 (Windows XP Desktop)
monitor session 1 destination interface Gi0/22 (Windows XP Laptop
w/Wireshark application)

I start a capture, selecting the interface connected to the switch.  The
capture returns traffic, but all that I'm seeing is what appears to be
mostly ARP, Broadcast, DNS Queries and some UDP traffic (all expected).
 What I'm not seeing is the TCP STREAMS.....I can see some TCP traffic
but not the entire stream....so I can't follow any of them.  For
example, I've been trying to uncover an issue with IMAP mail clients
having "network disconnects" to a remote server.  When I do anything in
my mail all I see is Echo traffic and Source = "localhost" and
destination is shown as the system on which my mail client resides.

Why can't I see the traffic across the switch like I'm expecting to?  Do
I have something misconfigured.  I haven't done this too often but I
though I had once before and saw all of the traffic as normal.

Please help.

Thanks,

Chad Webb