Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!husc6!purdue!smb
From: smb@cs.purdue.EDU (Scott M. Ballew)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Why do I need multiple host names for the same host?
Message-ID: <12480@medusa.cs.purdue.edu>
Date: 14 Nov 90 21:00:30 GMT
References: <705@keele.keele.ac.uk>
Sender: news@cs.purdue.EDU
Reply-To: smb@tristram.cs.purdue.edu (Scott M Ballew)
Organization: Department of Computer Science, Purdue University
Lines: 34

In article <705@keele.keele.ac.uk> csd35@seq1.keele.ac.uk (Jonathan Knight) writes:
>I have two questions.
>
>1)	When a host on the 192.82.242 network tries to talk to
>	'doc' is the packet addressed to 192.42.100.3? If not
>	is this packet unpacked by doc?  If not does this packet
>	actually get placed on the 192.42.100 network and re-read
>	by doc?

Ok, first it will send it to 192.42.100.3 since this is the only
translation for the name doc.  Doc will recognize it as its own and
process it correctly (it does NOT go back out on the other net).  If
it were sent out on the other net, it is not guaranteed that doc could
read it back in (some ethernet interfaces hear themselves talking,
others do not).

>2)	Is there a way to indicate to each host that doc is local
>	on their ethernet?

We do the following with our gateways:
128.10.2.8      gwen gwen-en 
128.10.3.8      gwen gwen-xinu

(I have deleted the fully qualified domain names).  This seems to keep
everyone who does not run DNS (a rapidly shrinking number) happy.  I
don't know about booting, however, since we generally do not make a
file server a gateway.

Running a nameserver is probably a better bet but you may have reasons
not to do so.

Scott Ballew
Cypress Network Operations Center
Purdue University Department of Computer Sciences