unwanted sender header via smtp submission [Was: Multiple Identities: Anonymity]

[Brady, Mike]

On 2014-03-26 03:34, hede wrote:
> Hi,
> 
> It seems the MUAs add those headers. At least in my case.
> 
> I've added a line "/^Sender:/  IGNORE"
> to /etc/postfix/header_checks.submission and now the header has 
> vanished.
> 
> But that's not a solution, it's just a test. Because it will even get
> removed if the header is desired and not set by accident...
> 
> Yet the question how to suppress this in roundcube and android k9mail
> is still open.
> 
> regards
> hede

I am suspecting that it is the MSA that is always adding the sender 
header when it should only conditionally do so.  In my case the MUA 
(Bynari's Outlook Connector) is providing a sender header so the MSA 
shouldn't, but Roundcube does not so it should.

 From RFC6409

8.1.  Add 'Sender'

    The MSA MAY add or replace the 'Sender' field, if the identity of the
    sender is known and this is not given in the 'From' field.

    The MSA MUST ensure that any address it places in a 'Sender' field
    is, in fact, a valid mail address.

Only guessing at this point.  I am trying to understand how the MSA 
functionality in Postfix works at the moment.

Regards

Mike