Re: [exim-dev] [PATCH] Implement redirect

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Author: Robert Millan
Date:  
To: David Woodhouse
CC: exim-dev
Subject: Re: [exim-dev] [PATCH] Implement redirect
On Thu, Jun 29, 2006 at 12:10:14AM +0100, David Woodhouse wrote:
>
> Cute idea, but I don't like the implementation much -- it would be
> better for it to be available in a general fashion from ACLs.


I looked at that first. However, since (AFAICT) the ACL system works in a
accept/reject/defer logic, my understanding was that a fourth command would had
to be added to the underlying code specificaly for this feature. Is this
appreciation correct?

> In
> particular, if I were to use it I'd want to use it _only_ for senders
> which are known to be SPF-afflicted. Those who didn't choose to break
> their email shouldn't get the 551 error.


Selective "redirecting" based purely on SPF-ness of sender is something I'm
already contemplating (I'll try to send a patch for that).

As for non-selective redirect, please note that:

- It's not only useful to workaround SPF problems. Other advantages include:

    - Huge saving in bandwidth / system load.


    - The final recipient isn't forced to blindly trust forwarder's mail as ham,
    so they can perform the delivery-time checks of their liking (greylisting,
    dnsbl, etc).


- While it's not a common feature, some MTAs already support it. sendmail
comes with non-selective (per-user) redirection in the vanilla package. qpsmtp
supports it with a plugin as well.

IMHO, it'd make sense to support both modes of operation. What do you think?

--
Robert Millan