Problem with Return-Path from certain ISPs
Jethro R Binks
jethro.binks at strath.ac.uk
Fri Dec 11 11:31:40 GMT 2009
On Fri, 11 Dec 2009, Ricardo Branco wrote:
> Ive been able to reproduce this again and again, not only with Hotmail.
> It seems that if the sending MTA (ie Hotmail) supplies a Return-Path
> then for some reason its taken out.
> I think there is a bug in MailScanner/Sendmail.pm arround line 352
> I tested this by telnetting to my mail server and in the DATA section
> putting a returnpath and it then did not end up on the final headers,
> but if i dont put it then its there.
The Return-Path: header should ONLY be added by the final receiving
server, at the point of delivery to the mailbox (in its role as MDA).
Its value is copied from the envelope sender address as received by the
delivering server. It should not be present on messages in-transit before
that point, so it is not inappropriate for it to be removed as it is
untrusted information -- if MailScanner is indeed doing so.
Perhaps Sendmail, or Dovecot's LDA, are not adding the header when they
> Ricardo Branco wrote, On 03/12/2009 15:00:
> > Centos+MailScanner+Sendmail+DovecotLDA
> > We started noticing issues with return-path not being passed though to
> > Sendmail/DovecotLDA. This causes a knock on affect on Sieve filters in
> > DovecotLDA which rely on Return-Path being passed though.
> > If I take MailScanner out the loop then all is well, Return-Path
> > exists to my mailbox, but if MS is running then it does not come
> > through.
> > Any reason why this would be happening?
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Jethro R Binks
Computing Officer, IT Services, University Of Strathclyde, Glasgow, UK
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