Re: Packet cap diff... for classic dhcp over winxp s/w bridge prob.

From: Horst Knobloch (horschti2_at_gmx.de)
Date: 04/25/05 

Date: Mon, 25 Apr 2005 21:54:57 +0200

Coenraad Loubser <c10u@ananzi.co.za> wrote:

[DHCP + MS Bridging Problem]

> Nope, cant find anything on their site.

See posting from prg. Client Identifiers seems to be
the proper way to go when it comes to the MS-style of
"bridging".

> Just out of curiosity.. I never studied this; How does a normal bridge
> then know where to route a returning packet? with an IP its simple.. but
> if the return mac is not that of the bridge, how will the bridge receive
> it... it should at least change the packet mac, shouldnt it?

No. The bridge puts the ethernet interfaces in promiscous mode
(like tcpdump/ethereal). So it sees all eth. frames on the
ethernet segments and learns (via the source MAC address) on
which interface which MAC addresses are located. If it haven't
learned on which interface a given MAC address resides, it sends
the ethernet frame through all interfaces except the one on which
it was received.

Ciao, Horst 

-- 
»When pings go wrong (It hurts me too)« E.Clapton/E.James/P.Tscharn

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