Wireshark-users: Re: [Wireshark-users] Track a packet in source & destination end sniffer capture

From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Thu, 1 Sep 2011 02:39:38 -0700
On Sep 1, 2011, at 2:14 AM, samarjit das wrote:

> I have taken sniffer capture at both ends(source & destination) of communication but how can I track a single packet at both sides of capture. Is there any unique #  tagged into the packet from which it can be identified that this is the packet reaching the destination side capture which was sent by source.

In general, no, there is not.  A packet can be sent over an arbitrary network, and most if not all link layers have no such unique number.

IPv4 has an IP ID field, but

	1) not all packets are IPv4 packets

and

	2) those IP ID field values can be reused, eventually, so if you have a large enough capture, they're not unique

and

	3) they're used for fragment reassembly, so all fragments of a fragmented IP datagram have the same IP ID.