uucp and preserving Reply-to: how?

[gst at gnosys.svle.ma.us (Gary S. Trujillo)]

> Note also that is illegal to use both a '!' and a '@' in a mail address, such
> as aaaa!bbbb at cccc.

It's not illegal at all - it's just that the results are undefined (even
if one knows what will happen specific cases), which is quite another matter.

> The UUCP side will parse this as "send to aaaa, which will send it to
> bbbb at cccc."  The SMTP side will parse this as "send to cccc, which
> will send it to aaaa!bbbb."

Well, address interpretation is done by the mail transfer agent, not by
the UUCP software.  I'm using Smail 3.1 and could probably tweak things
to override the default behavior (such addresses appear so infrequently
that I've never bothered figuring out how to do so).  I just know that
my MTA will always treat "host1!user at host2" as "user%host2 at host1" (which
resolves to "host1!host2!user" in bangpath-speak) and that I can rely on
that result - but I don't use such addresses (though I do use the bangpath
form on occasion, when I want routing to be done through a given host for
one reason or another) because I know that I can't count on the same
interpretation being placed on such an address by the mail system at the
receiving end - which messes up replies (to say nothing of the fact that
the MTA on the receiving end will probably re-write the address).

So I just think that one should not use "host1!user at host2" addresses,
but they're not formally illegal.  If they were, they'd be kicked out
altogether.

Gary
--
    Gary S. Trujillo                            gst at gnosys.svle.ma.us
Somerville, Massachusetts                {wjh12,bu.edu,spdcc,cdp}!gnosys!gst