Problem with Return-Path from certain ISPs

Ricardo Branco ricardo at
Fri Dec 11 10:46:33 GMT 2009

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/ 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.

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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