Path: utzoo!utgpu!attcan!uunet!munnari!vuwcomp!duncan
From: duncan@comp.vuw.ac.nz (Duncan McEwan)
Newsgroups: comp.mail.uucp
Subject: Treatment of envelope recipient addresses (Was: Mail survey #1)
Message-ID: <14177@comp.vuw.ac.nz>
Date: 2 Sep 88 00:48:12 GMT
References: <4740@b-tech.UUCP>
Reply-To: duncan@comp.vuw.ac.nz (Duncan McEwan)
Organization: Comp Sci, Victoria Univ, Wellington, New Zealand
Lines: 47

In article <4740@b-tech.UUCP> zeeff@b-tech.UUCP (Jon Zeeff) writes:
>Perhaps all this discussion can result in some conclusions on a 
>few basic questions.

Excellent idea, Jon!

>Mail your results to me.

I've just done that - I wonder what the chances of them reaching you
are :-)

> Additional questions are welcome.

One question that I have not seen much discussion on is what should
a UUCP <-> Internet gateway do with an "!" format route in the envelope
recipient address.  Here is what I think should happen.

If someone sends to "user%somesite@internet.edu" from a non-internet UUCP site,
that site should leave the recipient address untouched in the "To:" header,
but rewrite the recipient envelope as "edu-gateway!internet.edu!somesite!user".

When "edu-gateway" gets it the address will be "internet.edu!somesite!user"
Once they have figured out that they are sending to internet.edu via SMTP over
the Internet, they should convert the uucp route address to the Internet
equivelent - ie "@internet.edu:user@somesite" (or if they follow rfc822 to the
letter and don't allow unregistered sites as part of route addresses, perhaps
"user%somesite@internet.edu").  In "sendmail" terminology, this would be
done in the smtp mailer specific recipient ruleset.

The current behaviour of many UUCP <-> Internet gateways seems to be
to make "internet.edu!somesite!user" into "somesite!user@internet.edu",
Assuming it at least handles "@" before "!", the mail will at least get
to "internet.edu", but may or may not be interpreted correctly there,
depending on if internet.edu knows about uucp style addressing.

The site that originally converted "user%somesite@internet.edu" into the pure
uucp path could have made the recipient envelope into
"edu-gateway!internet.edu!user%somesite", but this is somewhat dangerous since
the path to edu-gateway could pass through a site that treated "%" with higher
precedence than "!". 

I think the behaviour I have described is practical to implement in sendmail
(I don't know if this is true of other mailers like mmdf, or if they already
behave in this way).  Have I missed something that makes it difficult?  Are
there any UUCP <-> Internet gateways using sendmail that do behave this way? 

Duncan  (duncan@comp.vuw.ac.nz, ...!uunet!vuwcomp!duncan)