Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!purdue!haven!uvaarpa!randall
From: randall@uvaarpa.virginia.edu (Randall Atkinson)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: %-Hack .vs. Route Address
Message-ID: <1988@uvaarpa.virginia.edu>
Date: 9 Jan 90 17:45:42 GMT
References: <35783@cornell.UUCP> <836@ccadfa.adfa.oz.au>
Reply-To: randall@uvaarpa.Virginia.EDU (Randall Atkinson)
Organization: University of Virginia, Charlottesville
Lines: 29

In article <836@ccadfa.adfa.oz.au> cjsv@cs.adfa.oz.au (Christopher J S Vance) writes:

>But it seems to me that you're only allowed to use route-addresses when all
>the hosts are registered with the NIC.  Since they won't want to register
>every PC in the world, or even every mainframe on lots of networks which are
>not on the Internet, it seems you've got to break some rules to make things
>work.  Personally, I think source-routes are nasty since they aren't pure
>left-to-right or right-to-left.  But then I've never had to use them....

Actually, any node on the GE internal DECnet can be reached as
node.DNET.GE.COM and there are no A records or in fact IP addresses
for virtually all of the machines on that network.  The RFC states
that you are only allowed to use route-addresses with fully-qualified
domain names in registered domains.  GE's solution is fairly general
and requires only a single MX record pointing *.DNET.GE.COM to a
relay-host directly on the Internet.

There are special cases that won't be covered, but this solution DOES
handle the case of PCs on an internal network or any other  such situation.
The main case it won't (legally) handle is gatewaying to a network whose
machines aren't under your theoretical administrative control.
NASA's SPAN DECnet is circumventing this by having *.SPAN.NASA.GOV and
I heartily approve of NASA's solution even though many nodes on that
DECnet aren't owned or operated by NASA.

The %-hack is widely overused and I'd like to see it used only when
really necessary because it causes a lot of mail delivery problems.

  Ran