Re: [exim-dev] SMTP PRDR

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Author: Jeremy Harris
Date:  
To: exim-dev
Old-Topics: Re: [exim-dev] SMTP PRDR
New-Topics: [exim-dev] SMTP PRDR; Exim 4.82
Subject: Re: [exim-dev] SMTP PRDR
> On 2012-03-19 16:19, Todd Lyons wrote:
>> MAIL FROM:<user@???> PRDR


I've pushed a working version of PRDR in Exim to

http://git.exim.org/users/jgh/exim.git/log/refs/heads/todd_prdr

Todd gets credit for kicking off the effort and doing the server side.
I did the client side. Undoubtedly there are bugs and missing
features; please speak up if you're interested.

I'll wait a little while but at some point I'd like to merge a squashed
version back into the Exim mainline.

Here's the spiel from experimental-spec.txt :

-------------

Per-Recipient Data Response is an SMTP extension proposed by Eric Hall
in a (now-expired) IETF draft from 2007. It's not hit mainstream
use, but has apparently been implemented in the META1 MTA.

There is mention at http://mail.aegee.org/intern/sendmail.html
of a patch to sendmail "to make it PRDR capable".

ref: http://www.eric-a-hall.com/specs/draft-hall-prdr-00.txt

If Exim is built with EXPERIMENTAL_PRDR there is a new config
boolean "prdr_enable" while controls whether PRDR is advertised
as part of an EHLO response, a new "acl_data_smtp_prdr" ACL
(called for each recipient, after data arrives but before the
data ACL), and a new smtp transport option "hosts_try_prdr".

PRDR may be used to support per-user content filtering. Without it
one must defer any recipient after the first that has a different
content-filter configuration. With PRDR, the RCPT-time check
for this can be disabled when the MAIL-time $smtp_command included
"PRDR". Any required difference in behaviour of the main DATA-time
ACL should however depend on the PRDR-time ACL having run, as Exim
will avoid doing so in some situations (eg. single-recipient mails).

--
Jeremy