Wireshark-users: Re: [Wireshark-users] Using Wireshark for a DSL "link no surf" problem [UPDATE]
From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Wed, 2 Jul 2014 16:31:03 -0700
On Jul 2, 2014, at 3:46 PM, Kok-Yong Tan <ktan@xxxxxxxxxxxxxxxxxxx> wrote:

> This segues to my next question:  Is there any way to use Wireshark to ascertain the VPI/VCI of the ATM circuit from the Layer 2 packets that were said to have been flowing?  Or must I have specialized software or hardware to do this?

If you're capturing on the Ethernet into the modem, I wouldn't expect to see any ATM information from the capture - if, for example, the modem has an HTTP-based configuration interface for use on the local user side, Ethernet traffic to and from its Web server won't even necessarily go out over the DSL circuit.

To capture traffic on the ATM side of the modem, you'd need specialized hardware, and probably some level of specialized software to talk to that hardware.

> I noticed that the rep had nothing more than his laptop connected via ethernet cable to the DSL modem when he noticed the different VPI/VCI settings on a possibly in-house-only software running on it.

According to the manual for your modem at the URL you sent in an earlier message, there's an HTTP-based configuration interface.  That's probably what the rep was using.