Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!ANDREW.CMU.EDU!ddp+
From: ddp+@ANDREW.CMU.EDU (Drew Daniel Perkins)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: default broadcast address
Message-ID: <0Wrc7By00UoJE0kXZO@andrew.cmu.edu>
Date: 15 Jul 88 22:06:05 GMT
References: 
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 18

> *Excerpts from ext.in.tcp-ip: 12-Jul-88 Re: default broadcast address*
> *Charles Hedrick@princeto (991)*

> I don't know whether this is what actually happens in
> 4.3BSD, but I know what *should* happen.  The application should use
> net.subnet.-1.

> That way they can all be -1 or 0, etc., but your application can still
> specify which interface to use.
I don't think this is appropriate for all implementations.  The ip layer
shouldn't be second guessing the application.  Some applications may want to
send to -1 and some may want to send to net.subnet.-1.  4.3BSD is broken
because it doesn't allow an application to send to -1 yet still specify which
interface to use.  It could use some out-of-band indication such as bind() or
an ioctl().  I.e. if you bind() to the address of a particular interface (vs.
INADDR_ANY) and send to -1 it could route the packet to the interface of the
address to which you are bound.

Drew