"Rodent of Unusual Size" ([EMAIL PROTECTED]) writes:

> I'm not real conversant with the various packet formats.
> Is there anything at the TCP packet level that might include
> the MAC address of either endpoint?  If so, I rather guess
> it isn't used, but I'm not even sure it exists.  In other
> words, is the MAC address completely inaccessible in a WAN
> environment using TCP, or only by convention?

You can't get this information with any of the TCP socket APIs.

Furthermore, even if you wrote the necessary code to obtain the
layer-2 headers (probably using SOCK_PACKET on Linux), this effort
would still be somewhat futile, since every router in-between your
"destination" computer and the "source" node will re-write the MAC
address in the packets to their own MAC addresses anyways.

So, if there's a router in between you and the source node, the source
MAC addresses will be those of the router and not the original node.

Regards,

--kevin
-- 
Kevin D. Clark (CetaceanNetworks.com!kclark)  |
Cetacean Networks, Inc.                       |   Give me a decent UNIX
Portsmouth, N.H. (USA)                        |  and I can move the world
alumni.unh.edu!kdc (PGP Key Available)        |






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