Newsgroups: vmsnet.mail.pmdf
Subject: RE: default host name as foreign host
From: Ned Freed <ned@sigurd.innosoft.com>
Date: 14 Sep 1992 23:56:33 -0700 (PDT)
Organization: The Internet
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> I have been attempting to do the following:

>	In VMSmail, addressing a message To: in%username
>					     (no quotes or host/domain)

> Instead of this being translated to:  username@localhost.localdomain,
> I would like it to always translate to a particular foreign host.domain.

You can do this sort of thing only if you resort to the VMSMAIL-TO-PMDF mapping
in the mapping file. It is possible to do this there but doing so is incredibly
dangerous. There are many portions of PMDF as well as other software that
assume IN%username will translate to IN%"username@localhost". If you change
this assumption you will probably break all sorts of things, and I cannot
answer for the consequences.

What you can do is assign a separate foreign protocol name to this function.
This will work and should not disturb existing PMDF functionality. All you need
to do is assign another MAIL$PROTOCOL_xxx logical to point at PMDF_MAILSHR. The
mapping file will then let you handle this separate foreign protocol in a
completely different ways. Please see the documentation (5.1) for details on
how the mapping works.

You can even reverse the effects of this mapping using the PMDF-TO-VMSMAIL
mapping.

All this means going to a lot of trouble to just to eliminate the need to type
in a host name. This may appear at first glance to be a nice friendly thing to
do for your users, but it usually ends up as a disasterous choice.

Users really need to become familiar with the realities of addressing since
they may not always be faced with a nice friendly system with all sorts of
hacks like this around. (Or the next set of hacks will be totally different.)
You're not doing anyone a favor when you hide reality from them -- you are
simply making it much harder for them when they inevitably come face to face
with real addresses.

It might be worth it if we were talking about really ugly addresses here.
However, Internet addresses are relatively clean and simple, and if the
addresses you're using aren't nice and simple there are probably better ways to
clean them up.

So my best advice is that while you can do this sort of thing with PMDF do
everyone a favor and don't even try to set it up.

> I have tried setting the official-host-name of my local channel to
> the foreign host, and then adding the local host name as the
> local-host-alias for EVERY channel in the channel/host table.
> This did not work (the FROM address of a local message was always
> assigned to the foreign host/domain) and also seems a bit unelegant,
> if not downright dangerous.

The per-channel local-host-alias affects only messages being queued to the
channel. It has no effect or meaning aside from this, and certainly will have
no effect on the default host associated with mailbox-only addresses. It will
affect outgoing mail and probably render it totally unrepliable.

The official local host name is what's used for this purpose, but it is
also the fundamental definition of your host's identity. You cannot change
it without completely changing your host's identity as well.

				Ned