Ethereal-users: [Ethereal-users] Sniffing L2TP tunnel traffic and estimating bandwidth

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From: Sam Stickland <sam_ml@xxxxxxxxxxxxxx>
Date: Mon, 4 Apr 2005 12:37:59 +0100 (GMT Daylight Time)
Hi,

I'm looking to estimate the bandwidth in use for a network that is routed inside an L2TP tunnel.

If I specify either of the two L2TP tunnel enpoints in the filter expression then I see tethereal decode the tunnel traffic. However, now I am already specifying a host in the filter expression, I can't specify additional filters for the traffic inside the L2TP tunnel.

For example, if hosts A and B are in the tunnel with endpoints E1 and E2 then:

tethereal -eth1
	Shows traffic between E1 and E2

tethereal "host E1" -ieth1
	Shows all traffic for hosts A and B

tethereal "host E1 and host A" -eth1
	Matches nothing

I've been able to achieve something of what I need by mixing filter and display strings, but I think I really need to do all of this in a filter expression (I'd like to be corrected).

Secondly, I'd like to be able to analyse the traffic matching the filter expression for bandwdith usage. I've been told that this is possible with tethereal, but I can't find it in the documentation.

Any help would be appreciated!

Sam