Subject: Re: a stupid question about ethernet addresses
To: Rui Paulo <rpaulo@fnop.net>
From: None <jonathan@dsg.stanford.edu>
List: tech-net
Date: 04/06/2006 12:38:40
In message <87u096liq4.fsf@phi.internal.fnop.net>Rui Paulo writes

>"Konstantin KABASSANOV" <Konstantin.Kabassanov@lip6.fr> writes:
>
>> If there is a packet with the same source and destination mac address
>> (typically a packet wrongly sent over an interface different from the
>> loopback), what could be the right behaviour of the kernel? Is the packet
>> treated twice (no way to make difference between incoming and outgoing
>> direction)?
>
>If I understad you correctly you are asking what should a system do if
>it recives a packet with the same src and dst MAC address ?
>Then I guess, it should be dropped.

Rui,

I can't see any reason why such packets should be dropped, given that
the local host decided to emit them?. Could you explain, please, why
you think such packets should be dropped?  The descrbed case is an
unusual, but not-illegal case. Indeed, it's even useful for testing
certain failure cases, and can be forced if desired.

If dimming memory serves well, there are protocols other than IP which
make use of the feature. (I'm not sure if NetBSD will ever support
them, though).