Using DCC with forwarding?

Gary Mills mills@cc.UManitoba.CA
Mon May 20 14:00:42 UTC 2002

On Sun, May 19, 2002 at 11:01:31PM -0600, Vernon Schryver wrote:
> > From: Gary Mills <mills@cc.UManitoba.CA>
> >               According to the new-style DCC log files, sendmail has
> > resolved the aliases by the time it connects to dccm.  I can see from
> > there which are local and which are not.  
> Are you sure of that?  You seem to be running 8.12.3 as I am, but in
> my fiddling with things, I don't see the aliases resolved.  Addresses
> are and must be resolved for sendmail to tolerate the Rcpt_To command
> even before Milter filters are called, but I don't know how a Milter
> filter can get the alias.

Here's an example:

 DATE: 05/19/02 14:09:41 CDT
 IP: ::ffff:
 env_From: <owner-textbreakingnews@CNNIMAIL12.CNN.COM>
 env_To: <shirley_dyck@UMANITOBA.CA>  dir=
 env_To: <ed_spencer@UMANITOBA.CA>  addr=fastedy  dir=
 env_To: <jane_lastra@UMANITOBA.CA>  dir=
 env_To: <dianne_boulay@UMANITOBA.CA>  dir=
 env_To: <gadi_glogowski@UMANITOBA.CA>  addr=umglogow  dir=
 env_To: <david_gregory@UMANITOBA.CA>  dir=
 env_To: <lori_kopp@UMANITOBA.CA>  dir=
 env_To: <janice_hollosy@UMANITOBA.CA>  dir=
 env_To: <chris_horbachewski@UMANITOBA.CA>  dir=
 env_To: <sl_klenman@UMANITOBA.CA>  dir=
 env_To: <christina_whittaker@UMANITOBA.CA>  dir=
 env_To: <vicki_reinhardt@UMANITOBA.CA>  dir=
 env_To: <mark_abrahams@UMANITOBA.CA>  addr=mabrah  dir=
 env_To: <rowena_krentz@UMANITOBA.CA>  dir=

I've been giving this item more thought.  Sendmail resolves each
envelope recipient address into a triple: mailer:host:user.  (It does
the same with the envelope sender, but the result is unreliable.
That's why sendmail uses the SMTP peer address to control relaying).
In the case of local addresses, the mailer is `local', and the host
is empty.  For non-local addresses, the mailer is `esmtp', and both
the host and user fields are present.  Clearly, only local addresses
need per-recipient logs, because the mail server has no knowledge of
or control over users at other sites.

If the other site is running DCC, as it is in my case, that site can
do the per-recipient logging.  I realize that having multiple recipients
complicates the SMTP processing.  In the example above, some of them
would be delivered locally on the main mail server, and the rest would
be relayed to the second server to be delivered there.  With DCC doing
rejection, I'd like to have the mail both rejected and relayed on the
main mail server, and then rejected on the second server, with logging
on both!  I suspect that that is impossible.

-Gary Mills-    -Unix Support-    -U of M Academic Computing and Networking-

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