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Path: utzoo!mnetor!seismo!mcvax!ukc!dcl-cs!stephen
From: stephen@comp.lancs.ac.uk (Stephen J. Muir)
Newsgroups: net.mail
Subject: Re: Driving on the left side of the road :-)
Message-ID: <396@comp.lancs.ac.uk>
Date: Wed, 10-Sep-86 17:40:24 EDT
Article-I.D.: comp.396
Posted: Wed Sep 10 17:40:24 1986
Date-Received: Thu, 11-Sep-86 21:45:39 EDT
References: <2279@utai.UUCP>
Reply-To: stephen@comp.lancs.ac.uk (Stephen J. Muir)
Organization: Department of Computing at Lancaster University, UK.
Lines: 32

In article <2279@utai.UUCP> lamy@utai.UUCP (Jean-Francois Lamy) writes:
>I am trying to communicate with a site in Britain, and I think I need
>a basic network topology briefing
>
>The message is destined to site psg.npl.co.uk 
>
>Our mailer sends mail in the uk domain to cs.ucl.ac.uk via X.25.  If I
>remember well, that machine is the gateway to the uk domain, where address
>conversion to the "programming-language-style domains" takes place

This is nothing to do with the domain order in this case.  What has happened is
that UKNET (the UK branch of USENET) has evolved separately from the two X.25
networks over here (JANET and PSS).  A while ago, the UKNET powers to be
decided that all UKNET sites should also have a domain-style name as used in
JANET and PSS.  Such domain names should be registered in the NRS (Name
Registration Scheme), which is a central registry of domain-style UK names.

Since, due to what I shall call "red tape", it is not very straightforward to
register your name in the NRS, not all UKNET sites are registered there yet.
I suspect many sites have given up trying!  The machine "cs.ucl.ac.uk" is the
"official" JANET<->ARPA gateway.  It does not recognise UKNET names.  The other
gateway, known both as "ukc.ac.uk" and "ukc.uucp", recognises both the UKNET
and domain-style names (whether registered in the NRS or not), but costs the UK
site money both for incoming and outgoing mail.

What I suggest you do is try "cs.ucl.ac.uk" first.  If that fails, try the
other one.
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