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

[Johannes Ranke]

Hi again,

Am Sonntag, 9. Januar 2022, 23:10:04 CET schrieb Lennart:
> 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). 

I only have zen.spamhaus.org configured here, so it must be something else. You 
are the first person reporting emails bounced by this server except for bounces 
due to size restrictions or the use of non-existent email addresses.

If you want to, we can have a go at analyzing this in detail off-list.

Kind regards,

Johannes

> 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-betwe
> >>>>> en
> >>>>> -s
> >>>>> ender-from-and-return-path
> >>>>> <https://stackoverflow.com/questions/4367358/whats-the-difference-betw
> >>>>> ee
> >>>>> 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
> >>>>> users at lists.kolab.org
> >>>>> https://lists.kolab.org/mailman/listinfo/users
> >> 
> >> _______________________________________________
> >> users mailing list
> >> users at lists.kolab.org
> >> https://lists.kolab.org/mailman/listinfo/users
> 
> _______________________________________________
> users mailing list
> users at lists.kolab.org
> https://lists.kolab.org/mailman/listinfo/users


-- 
Johannes Ranke
Wissenschaftlicher Berater
07624 8099027
https://jrwb.de