Re: Changing Return-Path

[Karl Kleinpaste <karl@jprc.com>]

Anders Melchiorsen <and@kampsax.dtu.dk> writes:
>> What I was wondering was whether the Return-Path: should be my
>> e-mail address or the account I am posting from (which is
>> unreachable due to a firewall).

Matt Armstrong <matta@geoworks.com> writes:
> The Return-Path: is not set by Gnus, but by sendmail

This is similar to the difficulty some of us have with Gnus'
generation of Sender.

This one is partly Gnus' "fault", if you can call it that.  sendmail
is invoked with `"-f" (user-login-name)' in message.el, to set the
origin user positively; a typical sendmail installation will then
adjust that to be your-name@your.host.where.you.sent.the.mail.  For
many (most?) of us, that's not really quite desirable, since (e.g.) my
Return-Path (which is the envelope origin from SMTP Mail From:<>,
converted to a header upon delivery) shows karl@pocari-sweat.jprc.com
but my normal address is karl@jprc.com.

The only way to hack around this is to modify the function
message-send-mail-with-sendmail from message.el, to substitute the
"-f" argument with a string that's more appropriate for you.

With regard to the standards for Return-Path, RFC822 observes that it
should be a _route_ back to the originator, i.e., it should show relay
hops; RFC1123 in turn says that failure notifications should be sent
back to the originator with the route information deleted, that is,
"If the address is an explicit source route, it SHOULD be stripped
down to its final hop."  ???  Then what's the point of providing the
source route in the first place?

It seems to me that Return-Path's value has become very limited in an
environment where source-routed mail is vastly deprecated, and just
plain not supported by many.  I know that, when I did serious sendmail
work years ago, I shot all source routes on sight.

You could very well substitute the use of (user-login-name) for the
"-f" argument in message-send-mail-with-sendmail with the variable
user-mail-address; the result should give the effect you need, and not
create any interoperability problems -- mail will still show a proper
way to return to you.

That said, this mailing list's requirement of matching Return-Path is
indeed pretty peculiar.

--karl