Re: Some correspondents have kolab_user@kolab_server instead of From address in their replies

Hi Johannes,

I assumed it was because the Amazon SES IP address is on a DNS blacklist 
(SORBS). Postfix could be configured to reject mail from IP's that are 
on that list (look for reject_rbl_client). If it's not that, I don't 
know what it is.

I'm quite displeased that some Amazon SES IP's are on SORBS (and 
apparently Amazon doesn't want to do anything about it). But I would 
recommend against using SORBS to reject mail on the MTA level (while it 
might be better used in a spam scoring system). I'm only using 
zen.spamhaus.org in that way.

Best,

Lennart

On 05-01-2022 07:56, Johannes Ranke wrote:
> Hi Lennart,
>
> just to clarify - as we discussed off-list, I cannot fully pin down the cause
> of your message being bounced. It seems that the postfix configuration coming
> with kolab does not accept the Amazon SES server you are using.
>
> Kind regards,
>
> Johannes
>
> Am Dienstag, 4. Januar 2022, 12:57:33 CET schrieb 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-betwee
>>>>> n
>>>>> -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
>>>>> [email protected]
>>>>> https://lists.kolab.org/mailman/listinfo/users
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>