Some correspondents have kolab_user at kolab_server instead of From address in their replies

[Lennart]

Hi Johannes,

You're welcome. For your information: the mailing list reports 
johannes.ranke [at] jrwb [dot] de as your address, but the email I sent 
to that address was bounced.

Best,

Lennart

On 04-01-2022 10:15, Johannes Ranke wrote:
> Hi Lennart,
>
> thanks for sharing your suggestions! In order to check if SPF and DKIM are
> aligned with the envelope from, I have now added a DMARC entry with an e-mail
> address for reporting to my DNS, so I should start receiving reports about any
> problems.
>
> Kind regards,
>
> Johannes
>
> Am Montag, 3. Januar 2022, 15:00:15 CET schrieb Lennart:
>> Hi Johannes,
>>
>> My hunch is that kolab.jrwb.de is set by Postfix as the envelope from
>> (aka SMTP FROM aka Return-Path, as opposed to the From header in the
>> message itself). The Sender header may be added either by Postfix or an
>> intermediate SMTP server to indicate the original envelope from.
>>
>> My envelope froms are also different from From headers and I'm not aware
>> of any problems. My only advice would be to have the top domain part
>> (i.e. jrwb.de) identical to the From header (to appease spam filters)
>> and to make sure that SPF records are set for the envelope from domain.
>> It's also important that emails to the envelope from address are
>> deliverable, since it is where bounces are sent.
>>
>> Hence, in deciding whether to use different envelope from addresses, I
>> think your primary concerns are: (a) are the SPF records set up
>> correctly for all domains that will be used as envelope from? (b) Where
>> do you want bounce emails to be delivered to?
>>
>> Best,
>>
>> Lennart
>>
>> On 08-12-2021 09:16, Johannes Ranke wrote:
>>> ...
>>>
>>>> This leaves me wondering if the Sender: should not be set to my
>>> primary e-
>>>
>>>> mail, and if yes, how I could achieve this.
>>> I found some discussion on Stackoverflow on this [1], leading to RFC
>>> 4021, updated by RFC 5322 [2]. All the RFCs which I looked up say that
>>> a Sender: header should only be included if the author of the message
>>> and the transmitter are not identical.
>>>
>>>
>>> So should I tell postfix not to include a Sender: address, and if yes,
>>> how? I have no delegates specified in the kolab-webadmin, and none of
>>> my users need this functionality.
>>>
>>>
>>> Johannes
>>>
>>>
>>>
>>> [1]
>>> https://stackoverflow.com/questions/4367358/whats-the-difference-between-s
>>> ender-from-and-return-path
>>> <https://stackoverflow.com/questions/4367358/whats-the-difference-between
>>> -sender-from-and-return-path>
>>>
>>>
>>> [2] https://datatracker.ietf.org/doc/html/rfc5322#section-3.6.2
>>> <https://datatracker.ietf.org/doc/html/rfc5322#section-3.6.2>
>>>
>>>
>>> _______________________________________________
>>> users mailing list
>>> users at lists.kolab.org
>>> https://lists.kolab.org/mailman/listinfo/users
>