Wireshark-users: Re: [Wireshark-users] de-duplicate packets by capture filter

From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Mon, 28 Nov 2011 22:10:42 -0800
On Nov 28, 2011, at 9:50 PM, Andrej van der Zee wrote:

>> If they're *not* bit-for-bit identical, and, for example, the source or destination MAC addresses differ, you might be able to use that.
> 
> I forgot to mention that from IP-level the packets are identical.

And, I assume, at the Ethernet level they're *not* identical, presumably by having different source and/or destination MAC addresses.

> I am
> just trying to understand first how one IP address can be mapped to
> multiple Ethernet II MAC-addresses.

By having a machine with multiple network interfaces on the same LAN segment and having its ARP implementation spit out different MAC addresses to different clients as a form of load balancing? :-)

Or by having the switch do other weird stuff internally?  What's the switch set up to do that causes it to duplicate the packets?  What is it doing to the MAC addresses?