*BSD News Article 83032


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From: Giao Nguyen <grail@cray-ymp.acm.stuorg.vt.edu>
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Two devices with same IP
Date: 17 Nov 1996 04:13:47 GMT
Organization: ACM Student Machine
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In comp.unix.bsd.freebsd.misc H. Jared Agnew <jagnew@csugrad.cs.vt.edu> wrote:
:   I have a friend that uses Redhat-4.0.  He was giving me flac about the fact
: that FreeBSD will not allow the same IP on more than one device.  I talked
: to a few friends and they told me that this was because haveing two devices
: with the same IP is against TCP/IP standards or something.  If anyone knows
: where I could read more about this could you please post.  Maybe a FAQ or
: RFC???  Thanks

: ---  Jared
: --jared@vt.edu

This is significantly brain damaged. If the kernel got a packet, how would it
resolve which device to route the packet to? While I'm not sure how it is
actually implemented, my only guess is that in order to have two devices with
the same IP address, the resolution would have to be done with some sort
of case statement. Wow, that's pretty obnoxious if you had some heavy 
duty network happening.

It makes more sense to disallow same IP on more than one device. But that's
just me.

-- 
Giao Nguyen
Computer Science Student
Will program for food