Path: utzoo!mnetor!uunet!munnari!kre
From: kre@munnari.oz (Robert Elz)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: bootp/rarp
Message-ID: <1957@munnari.oz>
Date: 13 Jan 88 13:14:02 GMT
References: <8801071746.AA16186@athos.rutgers.edu>
Organization: Comp Sci, Melbourne Uni, Australia
Lines: 25

I have a small box that has a prom monitor, and wants to use some
protocol to discover its IP address (or might want to, if it hasn't
been configured).

I currently use rarp, and would like to add bootp as an alternative.

My problem is that bootp requires sending udp to the IP broadcast
address, and that is something which (unfortunately) isn't a
constant.  That is, on many cables in the world, packets with
255's in them will be forwarded, or dropped, or just about anything
other than what you would hope.  There are many networks that still
use 0's as the broadcast address, regardless of whether or not that's
the right thing to do.

I don't much like this as a solution, but I'm contemplating sending
the broadcast to 255.255.255.255 initially, and if that works, fine.
If there's no response, I'll try 0.0.0.0 and see if that might happen
to succeed.  Then alternate.  I'm not sure if 4.2 really accepted
0.0.0.0 as a broadcast address, or only net.0, and I no longer have
virgin 4.2 sources around to check it.  Anyone know for sure?

Also, any opinions on mangling bootp this way?  Please don't bother
saying "ignore the 0 stuff", that's not acceptable.

kre