Re: [exim] exim and cyrus disagree about mail-from-syntax

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Author: Phil Pennock
Date:  
To: Patrick von der Hagen
CC: exim-users
Subject: Re: [exim] exim and cyrus disagree about mail-from-syntax
On 2007-11-16 at 16:32 +0100, Patrick von der Hagen wrote:
> Am Freitag, den 16.11.2007, 16:15 +0100 schrieb Patrick von der Hagen:
> > Hi all,
> >
> > I realised that lately messages arrive which cause unnessessary bounces
> > because they are accepted by exim and rejected by cyrus.
> I should have mentioned that I'm running exim 4.63. Any ideas how to
> have exim reject those messages? Since I do a callout to cyrus during
> recipient-verification to catch over-quota-situations, I guess I could
> just do "require verify = recipient/callout=use_sender" to catch this
> issue, but perhaps there is an exim-option for tighter sender-checking
> that I missed so far?


acl_smtp_mail, to define an ACL for the MAIL command, which supplies the
sender address. Either reject, or set a variable to reject at RCPT
time, based upon local_parts; there should be an example in the RCPT
checker in the standard config; add a backslash to that list to reject
all such mails.

If you set acl_mN (for some N; with any newer version of Exim, I'd say
acl_m_seen_backslash) to indicate when the mail from includes a
backslash, you can reject in the RCPT checker if you can sensibly check
that the mail is for a local address (easy) with that acl var set true
(easy) that will be delivered to Cyrus (depends upon your setup).

If you do want to actually accept such mails, then it depends upon
whether or not Cyrus is mapping \ooo as an Octal code (as the sender
appears to be doing) or is rejecting based upon the presence of the
backslash.  If Cyrus is mapping \octal then it's seeing "andré" and you
could try these in your imapd.conf:
  reject8bit:             no
  munge8bit:              no


You're beyond the standards game at this point at on your own, if you do
so.

-Phil