Re: does "port 25" work?

[Gert Doering <gert () greenie muc de>]

Hi,

On Thu, Jul 31, 2008 at 11:53:27PM -0400, U. George wrote:
> Without a detailed study, on my part, I am unable to jump to that 
> conclusion. 

There is nothing to "study" here, or any conclusion to "jump to".

Guy has described the way tcpdump currently works.  It works that way
because it was implemented that way.

> Specifying port does not necessarily also specify ether type 
> ( or anything else ).

It does, for tcpdump.  Ports are only defined in the context of TCP and
UDP (for tcpdump), and TCP and UDP are only defined for IP, and IP
(for tcpdump) implies "IP over Ethernet".

If you don't like that, change the source - but be aware of the implications
that Guy already pointed out: more complex BPF filter, which might have
performance impacts on high-bandwidth links.

gert

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Gert Doering - Munich, Germany                             gert () greenie muc de
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