Re: Reply-to:

[Richard Kettlewell <richard@elmail.co.uk>]

Oliver Oberdorf writes:
>> No!  Reply-To: is something entirely different, and will *not* solve
>> the problem.
>[...]
>> 	hostnames=sfere.elmail.co.uk:sfere.uk.geeks.org
>>		- the names which should be recognised as being local.
>>		  So user@sfere.elmail.co.uk is assumed to be `user'
>>		  on my machine, rather than requiring external
>>		  delivery.
>
>Reply-to: IS the right thing to do, IMO, since it will get
>people to reply to the correct address.

Unfortunately your opinion is wrong, since it won't get machines to
reply to the correct address.

There are three things here:

 * The `return path' is the envelope sender address.  This tends to
   get used for bounce messages, and therefore must point somewhere
   sensible.  (Consider the case of a message with no valid headers
   at all; a bounce must still go somewhere sane.)

 * The From: line in the header.  This needs to be set correctly so
   that replies go to the right place.

There are, I believe, systems which try to bounce to the From: header
or send a reply to the envelope sender, of course, but they're broken
badly.  (The latter will work remarkably badly on the wrong side of a
POP connection, for example.)

 * The Reply-To: line in the header.  This is used when one is to
   reply to some address(es) other than those in the From: line.

You will not get bounces sent to the Reply-To address.

>It is very simple and users can do it without root permission on your
>system - even if you're the only user that's nice.

Any user can put in a From: line.  If you add them to the list of
trusted_users in Smail's configuration file then they won't get a
Sender: line added in such cases.  root is not needed.

I think only the trusted users can set the envelope sender address,
however.

>Additionally, if you ever connect to the internet through multiple
>ISPs, you don't have to change system files every time you connect to
>a different one.

That's only a problem if you insist that connecting through different
ISPs smeans you change your email address.  I'd solve that by using a
single canonical email address all the time.

>The problem with the solution presented above is if you want to send
>mail *to your ISP* about something, it'll try and deliver locally.
>For example, mail to root, support, webmaster, postmaster... @ISP.com
>will all get delivered locally and you don't want that.

Indeed not.  AFAIK Smail can't solve this properly without some kind
of wrapping - rewrites are not a feature of the program.

Hope I've got that lot right ... l-)

-- 
Richard Kettlewell
http://www.elmail.co.uk/staff/richard/                    richard@uk.geeks.org

Eat a live toad before breakfast and nothing worse will happen to you all day.