• Gmail bounce unauthenticated @debian.org addresses

    From Baptiste Beauplat@21:1/5 to All on Fri Mar 4 12:50:01 2022
    Hi all,

    We recently discovered that Gmail started to bounce email from mentors.debian.net with the following message:

    550-5.7.26 This message does not have authentication information or
    fails to 550-5.7.26 pass authentication
    checks. To best protect our users from spam, the 550-5.7.26 message has
    been blocked. Please visit 550-5.7.26 https://support.google.com/mail/answer/81126#authentication for more 5
    50 5.7.26 information.

    My debian address is also affected, and probably others that did not
    setup DKIM for their @debian.org address.

    As a reminder debian.org addresses does support DKIM. After
    configuration on your mail server, you can publish your DKIM public key
    to db.debian.org [1][2].

    Best,

    [1]: https://lists.debian.org/debian-devel-announce/2020/04/msg00004.html
    [2]: https://db.debian.org/doc-mail.html
    --
    Baptiste Beauplat - lyknode

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  • From Baptiste Beauplat@21:1/5 to Stephan Lachnit on Fri Mar 4 13:40:01 2022
    Hi Stephan,

    On 3/4/22 13:27, Stephan Lachnit wrote:
    On Fri, Mar 4, 2022 at 12:47 PM Baptiste Beauplat <lyknode@cilg.org> wrote:

    My debian address is also affected, and probably others that did not
    setup DKIM for their @debian.org address.

    As a reminder debian.org addresses does support DKIM. After
    configuration on your mail server, you can publish your DKIM public key
    to db.debian.org [1][2].

    Can you point to some quick guide on how to do this for gmail? The
    support page seems kinda confusing to me.

    Looking at your email headers, I would guess that gmail is already doing it.

    X-Google-DKIM-Signature: v=1; a=rsa-sha256...

    There is somewhat some irony in Gmail blocking email without a DKIM
    signature while they are using a non-standard header that other
    provider/tools might miss. Just a thought.

    --
    Baptiste Beauplat - lyknode

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  • From Stephan Lachnit@21:1/5 to lyknode@cilg.org on Fri Mar 4 13:30:01 2022
    On Fri, Mar 4, 2022 at 12:47 PM Baptiste Beauplat <lyknode@cilg.org> wrote:

    My debian address is also affected, and probably others that did not
    setup DKIM for their @debian.org address.

    As a reminder debian.org addresses does support DKIM. After
    configuration on your mail server, you can publish your DKIM public key
    to db.debian.org [1][2].

    Can you point to some quick guide on how to do this for gmail? The
    support page seems kinda confusing to me.

    Regards,
    Stephan

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  • From Ansgar@21:1/5 to Stephan Lachnit on Fri Mar 4 13:40:01 2022
    On Fri, 2022-03-04 at 13:27 +0100, Stephan Lachnit wrote:
    On Fri, Mar 4, 2022 at 12:47 PM Baptiste Beauplat <lyknode@cilg.org>
    wrote:
    As a reminder debian.org addresses does support DKIM. After
    configuration on your mail server, you can publish your DKIM public
    key
    to db.debian.org [1][2].

    Can you point to some quick guide on how to do this for gmail? The
    support page seems kinda confusing to me.

    This usually requires you running your own mail server (for outgoing
    mail).

    I don't think mail providers like GMail allow you to set up DKIM for
    individual IP addresses.

    Ansgar

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  • From Bastian Blank@21:1/5 to Baptiste Beauplat on Fri Mar 4 15:00:01 2022
    On Fri, Mar 04, 2022 at 12:38:02PM +0100, Baptiste Beauplat wrote:
    We recently discovered that Gmail started to bounce email from mentors.debian.net with the following message:

    Can you please share the complete headers of the bounced message? Aka
    the thing in the message/rfc822 part of the DSN message. Right now we
    don't know what they see from your explanation.

    Bastian

    --
    A woman should have compassion.
    -- Kirk, "Catspaw", stardate 3018.2

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  • From Baptiste Beauplat@21:1/5 to Bastian Blank on Fri Mar 4 15:20:01 2022
    This is a multi-part message in MIME format.
    Hi Bastian,

    On 3/4/22 14:40, Bastian Blank wrote:
    On Fri, Mar 04, 2022 at 12:38:02PM +0100, Baptiste Beauplat wrote:
    We recently discovered that Gmail started to bounce email from
    mentors.debian.net with the following message:

    Can you please share the complete headers of the bounced message? Aka
    the thing in the message/rfc822 part of the DSN message. Right now we
    don't know what they see from your explanation.

    I'm attached the bounce.

    Am I mistaken in thinking that's only a case of simply rejecting
    unsigned DKIM email?

    --
    Baptiste Beauplat - lyknode RnJvbSBNQUlMRVItREFFTU9OICBGcmkgTWFyICA0IDAzOjE0OjA0IDIwMjIKUmV0dXJuLVBh dGg6IDw+ClgtT3JpZ2luYWwtVG86IGV4cG8rYm91bmNlQG1lbnRvcnMuZGViaWFuLm5ldApE ZWxpdmVyZWQtVG86IGV4cG8rYm91bmNlQG1lbnRvcnMuZGViaWFuLm5ldApSZWNlaXZlZDog Ynkgd3YtZGViaWFuLW1lbnRvcnMxLndhdmVjbG91ZC5kZSAoUG9zdGZpeCkKCWlkIEE2QTc1 OEI1RTI7IEZyaSwgIDQgTWFyIDIwMjIgMDM6MTQ6MDQgKzAwMDAgKFVUQykKRGF0ZTogRnJp LCAgNCBNYXIgMjAyMiAwMzoxNDowNCArMDAwMCAoVVRDKQpGcm9tOiBNQUlMRVItREFFTU9O QG1lbnRvcnMuZGViaWFuLm5ldCAoTWFpbCBEZWxpdmVyeSBTeXN0ZW0pClN1YmplY3Q6IFVu ZGVsaXZlcmVkIE1haWwgUmV0dXJuZWQgdG8gU2VuZGVyClRvOiBleHBvK2JvdW5jZUBtZW50 b3JzLmRlYmlhbi5uZXQKQXV0by1TdWJtaXR0ZWQ6IGF1dG8tcmVwbGllZApNSU1FLVZlcnNp b246IDEuMApDb250ZW50LVR5cGU6IG11bHRpcGFydC9yZXBvcnQ7IHJlcG9ydC10eXBlPWRl bGl2ZXJ5LXN0YXR1czsKCWJvdW5kYXJ5PSI1NUQxNjgyM0VDLjE2NDYzNjM2NDQvd3YtZGVi aWFuLW1lbnRvcnMxLndhdmVjbG91ZC5kZSIKQ29udGVudC1UcmFuc2Zlci1FbmNvZGluZzog OGJpdApNZXNzYWdlLUlkOiA8MjAyMjAzMDQwMzE0MDQuQTZBNzU4QjVFMkB3di1kZWJpYW4t 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  • From Colin Watson@21:1/5 to Baptiste Beauplat on Fri Mar 4 15:40:01 2022
    On Fri, Mar 04, 2022 at 03:15:59PM +0100, Baptiste Beauplat wrote:
    On 3/4/22 14:40, Bastian Blank wrote:
    On Fri, Mar 04, 2022 at 12:38:02PM +0100, Baptiste Beauplat wrote:
    We recently discovered that Gmail started to bounce email from
    mentors.debian.net with the following message:

    Can you please share the complete headers of the bounced message? Aka
    the thing in the message/rfc822 part of the DSN message. Right now we don't know what they see from your explanation.

    I'm attached the bounce.

    Am I mistaken in thinking that's only a case of simply rejecting
    unsigned DKIM email?

    I reproduced a similar problem, then set up DKIM for myself and
    everything then worked, so I think you're correct.

    The links in the original d-d-a email were mostly stale, but I found https://bynicolas.com/server/exim-multi-domain-dkim-custom-selector/
    helpful in getting this going with my local Exim setup.

    --
    Colin Watson (he/him) [cjwatson@debian.org]

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  • From Bastian Blank@21:1/5 to Baptiste Beauplat on Fri Mar 4 15:50:01 2022
    Hi

    On Fri, Mar 04, 2022 at 03:15:59PM +0100, Baptiste Beauplat wrote:
    Am I mistaken in thinking that's only a case of simply rejecting
    unsigned DKIM email?

    This might be, but…

    Return-Path: <expo+bounce@mentors.debian.net>
    Received: from mentors.debian.net (localhost [127.0.0.1])
    by wv-debian-mentors1.wavecloud.de (Postfix) with ESMTP id 55D16823EC
    for <**********@gmail.com>; Fri, 4 Mar 2022 03:14:03 +0000 (UTC) Content-Type: text/plain; charset="utf-8"
    MIME-Version: 1.0
    Content-Transfer-Encoding: 7bit
    Subject: Next step: Confirm your email address
    From: mentors.debian.net <support@mentors.debian.net>
    To: **********@gmail.com
    Date: Fri, 04 Mar 2022 03:14:03 -0000
    Message-ID: <164636364329.4074035.11224505717463252630@mentors.debian.net>

    I don't see anything about debian.org in those headers? Do you?

    - mentors.debian.net is not debian.org.
    - gmail.com clearly isn't.

    Bastian

    --
    "That unit is a woman."
    "A mass of conflicting impulses."
    -- Spock and Nomad, "The Changeling", stardate 3541.9

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  • From LeJacq, Jean Pierre@21:1/5 to All on Fri Mar 4 09:41:40 2022
    Copy: lyknode@cilg.org (Baptiste Beauplat)

    On Friday, March 4, 2022 9:15:59 AM EST Baptiste Beauplat wrote:

    mentors.debian.net with the following message:
    Can you please share the complete headers of the bounced message? Aka
    the thing in the message/rfc822 part of the DSN message. Right now we don't know what they see from your explanation.

    I'm attached the bounce.

    Am I mistaken in thinking that's only a case of simply rejecting
    unsigned DKIM email?

    I've just gone through the process of securing email with Google so I might be able to help a bit.

    Google uses a number of criteria when blocking. A missing DKIM is just one.
    See the referenced document:

    https://support.google.com/mail/answer/81126

    One of the problems here is that mentors.debian.net does not have the standard email security DNS records - SPF, DKIM, DMARC, MTA-TLS, DANE. This doesn't automatically cause Google to classify as spam but we really should have these in place to protect email.

    As an example, we may be spoofing mentors.debian.net with wv-debian- mentors1.wavecloud.de (not 100% clear with the headers provided). SPF could handle this.

    --
    JP

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    =JgEd
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  • From Baptiste Beauplat@21:1/5 to Jean Pierre on Fri Mar 4 15:50:02 2022
    On 3/4/22 15:41, LeJacq, Jean Pierre wrote:
    Google uses a number of criteria when blocking. A missing DKIM is just one. See the referenced document:

    https://support.google.com/mail/answer/81126

    One of the problems here is that mentors.debian.net does not have the standard
    email security DNS records - SPF, DKIM, DMARC, MTA-TLS, DANE. This doesn't automatically cause Google to classify as spam but we really should have these
    in place to protect email.

    As an example, we may be spoofing mentors.debian.net with wv-debian- mentors1.wavecloud.de (not 100% clear with the headers provided). SPF could handle this.

    Indeed we are looking into it for mentors.

    However for SPF, if I'm not mistaken, this is not possible for
    @debian.org addresses since Debian does not offers an MSA and therefor
    not a single (or enumerable list of) exit point.

    --
    Baptiste Beauplat - lyknode

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  • From Guillem Jover@21:1/5 to Colin Watson on Fri Mar 4 16:00:01 2022
    Hi!

    On Fri, 2022-03-04 at 14:36:01 +0000, Colin Watson wrote:
    I reproduced a similar problem, then set up DKIM for myself and
    everything then worked, so I think you're correct.

    The links in the original d-d-a email were mostly stale, but I found https://bynicolas.com/server/exim-multi-domain-dkim-custom-selector/
    helpful in getting this going with my local Exim setup.

    You might want to also fix the DKIM_SIGN_HEADERS macro in the Exim
    config, as its default is currently broken (see #939808). The patch
    attached there is not helpful for local usage, so you might want
    something like what I've got in my config:

    ,--- exim4.conf ---
    […]

    # The default headers to sign is broken, and includes things that should
    # not be signed by default if they are missing, or they will break mailing
    # lists.
    DKIM_SIGN_HEADERS = \
    From:From:Reply-To:Subject:Subject:Date:Message-ID:To:Cc:MIME-Version:\
    Content-Type:Content-Transfer-Encoding:Content-ID:Content-Description:\
    In-Reply-To:References:X-Debbugs-Cc:\
    =Sender:\
    =Resent-Date:=Resent-From:=Resent-Sender:=Resent-To:=Resent-Cc:\
    =Resent-Message-ID:\
    =List-Id:=List-Help:=List-Unsubscribe:=List-Subscribe:=List-Post:\
    =List-Owner:=List-Archive

    […]
    `---

    Thanks,
    Guillem

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  • From Ansgar@21:1/5 to Baptiste Beauplat on Fri Mar 4 16:20:01 2022
    On Fri, 2022-03-04 at 15:45 +0100, Baptiste Beauplat wrote:
    However for SPF, if I'm not mistaken, this is not possible for
    @debian.org addresses since Debian does not offers an MSA and
    therefor not a single (or enumerable list of) exit point.

    Using SPF would be possible. Gentoo does that:

    gentoo.org. IN TXT "v=spf1 [...] include:%{l}.%{o}.spf.gentoo.org ?all"

    and their users can then add SPF entries for individual localparts.

    But either way is quite complicated for "just" using a mail address for outgoing mail.

    Also some infrastructure in Debian will break DKIM signatures. For
    example, bugs.debian.org (always) and lists.debian.org (sometimes, for
    example when List-* header fields are part of the DKIM signature). So
    one can't rely on valid SPF/DKIM anyway and, as far as I understand,
    rely on debian.org infrastructure being on providers' whitelists
    instead (as it "impersonates" other domains in mail sender addresses).

    Ansgar

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  • From LeJacq, Jean Pierre@21:1/5 to All on Fri Mar 4 16:20:01 2022
    On Friday, March 4, 2022 9:45:21 AM EST Baptiste Beauplat wrote:
    On 3/4/22 15:41, LeJacq, Jean Pierre wrote:
    Google uses a number of criteria when blocking. A missing DKIM is just
    one.
    See the referenced document:

    https://support.google.com/mail/answer/81126

    One of the problems here is that mentors.debian.net does not have the standard email security DNS records - SPF, DKIM, DMARC, MTA-TLS, DANE. This doesn't automatically cause Google to classify as spam but we really should have these in place to protect email.

    As an example, we may be spoofing mentors.debian.net with wv-debian- mentors1.wavecloud.de (not 100% clear with the headers provided). SPF
    could
    handle this.

    Indeed we are looking into it for mentors.

    However for SPF, if I'm not mistaken, this is not possible for
    @debian.org addresses since Debian does not offers an MSA and therefor
    not a single (or enumerable list of) exit point.

    SPF can handle delegation like this without too much trouble.

    --
    JP

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  • From Colin Watson@21:1/5 to Guillem Jover on Fri Mar 4 17:00:01 2022
    On Fri, Mar 04, 2022 at 03:59:09PM +0100, Guillem Jover wrote:
    On Fri, 2022-03-04 at 14:36:01 +0000, Colin Watson wrote:
    I reproduced a similar problem, then set up DKIM for myself and
    everything then worked, so I think you're correct.

    The links in the original d-d-a email were mostly stale, but I found https://bynicolas.com/server/exim-multi-domain-dkim-custom-selector/ helpful in getting this going with my local Exim setup.

    You might want to also fix the DKIM_SIGN_HEADERS macro in the Exim
    config, as its default is currently broken (see #939808). The patch
    attached there is not helpful for local usage, so you might want
    something like what I've got in my config:
    [...]

    Useful to know - thanks!

    --
    Colin Watson (he/him) [cjwatson@debian.org]

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  • From LeJacq, Jean Pierre@21:1/5 to All on Fri Mar 4 16:40:01 2022
    On Friday, March 4, 2022 10:14:09 AM EST Ansgar wrote:
    On Fri, 2022-03-04 at 15:45 +0100, Baptiste Beauplat wrote:
    However for SPF, if I'm not mistaken, this is not possible for
    @debian.org addresses since Debian does not offers an MSA and
    therefor not a single (or enumerable list of) exit point.

    Using SPF would be possible. Gentoo does that:

    gentoo.org. IN TXT "v=spf1 [...] include:%{l}.%{o}.spf.gentoo.org ?all"

    and their users can then add SPF entries for individual localparts.

    But either way is quite complicated for "just" using a mail address for outgoing mail.

    Also some infrastructure in Debian will break DKIM signatures. For
    example, bugs.debian.org (always) and lists.debian.org (sometimes, for example when List-* header fields are part of the DKIM signature). So
    one can't rely on valid SPF/DKIM anyway and, as far as I understand,
    rely on debian.org infrastructure being on providers' whitelists
    instead (as it "impersonates" other domains in mail sender addresses).

    There are standard best practices for forwarding support in SPF.

    http://www.open-spf.org/Best_Practices/Forwarding/

    --
    JP

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  • From Ansgar@21:1/5 to Jean Pierre on Fri Mar 4 18:40:01 2022
    On Fri, 2022-03-04 at 10:21 -0500, LeJacq, Jean Pierre wrote:
    There are standard best practices for forwarding support in SPF.

    http://www.open-spf.org/Best_Practices/Forwarding/

    Having each individual user have to configure forwarders (i.e., per-
    user whitelists), including services like mailing lists, our bug
    tracker and so on, seems impractical. I also doubt many mail providers
    allow user to do so.

    And SRS also relies on whitelists again (otherwise it just allows
    bypassing any SPF policy).

    Ansgar

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  • From Marco d'Itri@21:1/5 to Baptiste Beauplat on Fri Mar 4 18:40:01 2022
    On Mar 04, Baptiste Beauplat <lyknode@cilg.org> wrote:

    Looking at your email headers, I would guess that gmail is already doing it.

    X-Google-DKIM-Signature: v=1; a=rsa-sha256...

    There is somewhat some irony in Gmail blocking email without a DKIM
    signature while they are using a non-standard header that other provider/tools might miss. Just a thought.
    No irony, you are just missing the point.
    gmail uses this X header for internal purposes, and there is no DKIM
    signature because the message has a @debian.org 822.from address hence
    gmail obviously lacks a valid key for it.

    --
    ciao,
    Marco

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    =79tD
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  • From LeJacq, Jean Pierre@21:1/5 to All on Fri Mar 4 19:00:01 2022
    On Friday, March 4, 2022 12:37:38 PM EST Ansgar wrote:
    On Fri, 2022-03-04 at 10:21 -0500, LeJacq, Jean Pierre wrote:
    There are standard best practices for forwarding support in SPF.

    http://www.open-spf.org/Best_Practices/Forwarding/

    Having each individual user have to configure forwarders (i.e., per-
    user whitelists), including services like mailing lists, our bug
    tracker and so on, seems impractical. I also doubt many mail providers
    allow user to do so.

    I agree. What does make sense if any forwards that the Debian infrastructure uses.

    And SRS also relies on whitelists again (otherwise it just allows
    bypassing any SPF policy).

    Again agree, so it's a scaling issue. Again, it makes sense to do for the Debian infrastructure, not necessarily every user.

    --
    JP

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  • From Nilesh Patra@21:1/5 to Stephan Lachnit on Fri Mar 4 22:40:01 2022
    On Fri, 2022-03-04 at 13:27 +0100, Stephan Lachnit wrote:
    Can you point to some quick guide on how to do this for gmail? The
    support page seems kinda confusing to me.

    This usually requires you running your own mail server (for outgoing
    mail).
    I don't think mail providers like GMail allow you to set up DKIM for individual IP addresses.

    I wonder if this is a good opportunity to share what I am doing for this.
    I do not use gmail anymore, stopped using months back but that does not matter.

    Also, do not have the b/w to setup own mailserver, so what I do is that I sign my mails
    "locally" as MUAs can also support DKIM signing, and I send that via SMTP.

    I use mutt primilarily, and months back I found this smart trick to do so, see this link[1] -- created dkim keys locally,
    modified that script a little and the .msmtprc and .muttrc a little, and voila!

    Saw something similar for emacs as well[2]
    I actually found a very helpful advice in the 'comments' section(by Ucko) of Anarcat's blog[3] that helped.

    Happy to share more details if someone needs.

    [1]: https://bbs.archlinux.org/viewtopic.php?id=210976
    [2]: https://github.com/BramvdKroef/dotemacs/blob/master/dkim.el
    [3]: https://anarc.at/blog/2020-04-14-opendkim-debian/

    Regards,
    Nilesh

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  • From Baptiste BEAUPLAT@21:1/5 to Marco d'Itri on Sat Mar 5 10:20:01 2022
    On 3/4/22 18:29, Marco d'Itri wrote:
    On Mar 04, Baptiste Beauplat <lyknode@cilg.org> wrote:

    Looking at your email headers, I would guess that gmail is already doing it. >>
    X-Google-DKIM-Signature: v=1; a=rsa-sha256...

    There is somewhat some irony in Gmail blocking email without a DKIM
    signature while they are using a non-standard header that other
    provider/tools might miss. Just a thought.

    No irony, you are just missing the point.
    gmail uses this X header for internal purposes, and there is no DKIM signature because the message has a @debian.org 822.from address hence
    gmail obviously lacks a valid key for it.

    Thanks for pointing this out Marco. I did check a mail coming from
    @gmail.com and indeed the correct header was used.

    Stephan, sorry then. I don't use gmail and I won't be able to point you
    to the correct how-to :/
    --
    Baptiste BEAUPLAT - lyknode

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  • From Steve McIntyre@21:1/5 to Baptiste Beauplat on Sat Mar 5 16:00:01 2022
    Baptiste Beauplat wrote:

    We recently discovered that Gmail started to bounce email from >mentors.debian.net with the following message:

    550-5.7.26 This message does not have authentication information or
    fails to 550-5.7.26 pass authentication
    checks. To best protect our users from spam, the 550-5.7.26 message has
    been blocked. Please visit 550-5.7.26 >https://support.google.com/mail/answer/81126#authentication for more 5
    50 5.7.26 information.

    Yup. I've seen this too. Thanks for starting the thread here, which
    has prompted useful clues on how to deal with this.

    It's maddening to see Google continue to f*ck up mail requirements for everybody else. Of course, they continue to be (one of?) the biggest
    sources of spam on the net and show no interest in doing anything
    about it. "Don't be evil" indeed... :-(

    --
    Steve McIntyre, Cambridge, UK. steve@einval.com "We're the technical experts. We were hired so that management could
    ignore our recommendations and tell us how to do our jobs." -- Mike Andrews

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  • From Craig Small@21:1/5 to Ansgar on Sun Mar 6 00:30:01 2022
    On Fri, 4 Mar 2022 at 23:34, Ansgar <ansgar@43-1.org> wrote:

    On Fri, 2022-03-04 at 13:27 +0100, Stephan Lachnit wrote:
    On Fri, Mar 4, 2022 at 12:47 PM Baptiste Beauplat <lyknode@cilg.org>
    wrote:
    As a reminder debian.org addresses does support DKIM. After
    configuration on your mail server, you can publish your DKIM public
    key
    to db.debian.org [1][2].

    Can you point to some quick guide on how to do this for gmail? The
    support page seems kinda confusing to me.

    This usually requires you running your own mail server (for outgoing
    mail).

    I don't think mail providers like GMail allow you to set up DKIM for individual IP addresses.

    This is basically how I do it. My setup is I have G-Suite or whatever its
    name is this week and a separate outbound server. I'm not sure what the "to
    do this for gmail" means here, so there is three parts to this:
    * What Gmail does with DKIM
    * How I send emails from @debian.org using mutt etc
    * How I send emails from @debian.org using Gmail

    First, Gmail likes DKIM signed mails; some of these bounces are caused by
    DKIM problems. DKIM is basically a signature to say the senders server is
    allow to send those emails. You have to set it up (sign) on the outbound servers and check it on the inbound servers.

    For any of my servers/laptops I send outbound email to my own outbound
    server. This server signs emails using opendkim with the dropbear.xyz key
    or the debian key depending on the from address. It's no good sending email from joe@cow.com with a key good for joe@sheep.net

    Last of all, to send emails within Gmail using csmall@debian.org as my from address, you go into Settings->Accounts->Send mail as. The outbound
    mailserver is my server (that signs my debian emails). Of course my
    outbound server requires a username and password to send emails so that is recorded in the settings too (and is unique for each sending system/server).

    The result is this goodness I can see with an email from my laptop into
    Gsuite using my debian email address:
    Authentication-Results: mx.google.com;
    dkim=pass header.i=@debian.org header.s=debian1.csmall.user header.b=uVHcNrjO;

    header.i is identity, e.g. what domain are you trying to prove you can use. header.s is selector, which is what method/key am I using to prove this. header.b is the hash/signature.

    I'm a network engineer, not a mail server admin so this might not be 100%,
    but it does give me the happy mailserver headers I want.

    - Craig

    <div dir="ltr"><div dir="ltr">On Fri, 4 Mar 2022 at 23:34, Ansgar &lt;<a href="mailto:ansgar@43-1.org" target="_blank">ansgar@43-1.org</a>&gt; wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-
    left:1px solid rgb(204,204,204);padding-left:1ex">On Fri, 2022-03-04 at 13:27 +0100, Stephan Lachnit wrote:<br>
    &gt; On Fri, Mar 4, 2022 at 12:47 PM Baptiste Beauplat &lt;<a href="mailto:lyknode@cilg.org" target="_blank">lyknode@cilg.org</a>&gt;<br>
    &gt; wrote:<br>
    &gt; &gt; As a reminder <a href="http://debian.org" rel="noreferrer" target="_blank">debian.org</a> addresses does support DKIM. After<br>
    &gt; &gt; configuration on your mail server, you can publish your DKIM public<br>
    &gt; &gt; key<br>
    &gt; &gt; to <a href="http://db.debian.org" rel="noreferrer" target="_blank">db.debian.org</a> [1][2].<br>
    &gt; <br>
    &gt; Can you point to some quick guide on how to do this for gmail? The<br> &gt; support page seems kinda confusing to me.<br>

    This usually requires you running your own mail server (for outgoing<br> mail).<br>

    I don&#39;t think mail providers like GMail allow you to set up DKIM for<br> individual IP addresses.</blockquote><div>This is basically how I do it. My setup is I have G-Suite or whatever its name is this week and a separate outbound server. I&#39;m not sure what the &quot;to do this for gmail&quot; means here, so there is three
    parts to this:</div><div>* What Gmail does with DKIM</div><div>* How I send emails from @<a href="http://debian.org" target="_blank">debian.org</a> using mutt etc</div><div>* How I send emails from @<a href="http://debian.org" target="_blank">debian.
    org</a> using Gmail</div><div><br></div><div>First, Gmail likes DKIM signed mails; some of these bounces are caused by DKIM problems. DKIM is basically a signature to say the senders server is allow to send those emails. You have to set it up (sign) on
    the outbound servers and check it on the inbound servers.</div><div><br></div><div>For any of my servers/laptops I send outbound email to my own outbound server. This server signs emails using opendkim with the <a href="http://dropbear.xyz" target="_
    blank">dropbear.xyz</a> key or the debian key depending on the from address. It&#39;s no good sending email from <a href="mailto:joe@cow.com" target="_blank">joe@cow.com</a> with a key good for <a href="mailto:joe@sheep.net" target="_blank">joe@sheep.net<
    </div><div><br></div><div>Last of all, to send emails within Gmail using <a href="mailto:csmall@debian.org" target="_blank">csmall@debian.org</a> as my from address, you go into Settings-&gt;Accounts-&gt;Send mail as. The outbound mailserver is my
    server (that signs my debian emails).  Of course my outbound server requires a username and password to send emails so that is recorded in the settings too (and is unique for each sending system/server).</div><div><br></div><div>The result is this
    goodness I can see with an email from my laptop into Gsuite using my debian email address:</div><div>Authentication-Results: <a href="http://mx.google.com">mx.google.com</a>;<br>       dkim=pass header.i=@<a href="http://debian.org">debian.org</a>
    header.s=debian1.csmall.user header.b=uVHcNrjO;<br></div><div><br></div><div>header.i is identity, e.g. what domain are you trying to prove you can use. header.s is selector, which is what method/key am I using to prove this. header.b is the hash/
    signature.</div><div><br></div><div>I&#39;m a network engineer, not a mail server admin so this might not be 100%, but it does give me the happy mailserver headers I want.</div><div><br></div><div> - Craig</div><div><br></div></div></div>

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  • From =?utf-8?Q?Bj=C3=B8rn_Mork?=@21:1/5 to Jean Pierre" on Mon Mar 7 21:30:01 2022
    "LeJacq, Jean Pierre" <jeanpierre.lejacq@quoininc.com> writes:

    There are standard best practices for forwarding support in SPF.

    http://www.open-spf.org/Best_Practices/Forwarding/

    Well, if it only was that simple.

    There is NO working SRS software/example config for sendmail in Debian
    or anywhere else AFAICS.

    The only thing we have is the python3-srs packages, which are still full
    of python2 specific code. None of the included tools even run on
    bullseye. For example:

    bjorn@canardo:~$ /usr/bin/srs2envtol
    Traceback (most recent call last):
    File "/usr/bin/srs2envtol", line 14, in <module>
    from ConfigParser import ConfigParser, DuplicateSectionError ModuleNotFoundError: No module named 'ConfigParser'
    bjorn@canardo:~$ dpkg -S /usr/bin/srs2envtol
    pysrs-bin: /usr/bin/srs2envtol
    bjorn@canardo:~$ apt-cache policy pysrs-bin
    pysrs-bin:
    Installed: 1.0.3-2
    Candidate: 1.0.3-2
    Version table:
    *** 1.0.3-2 700
    700 http://deb.debian.org/debian bullseye/main amd64 Packages
    100 /var/lib/dpkg/status

    (yes, I could fix that and the remaining issues - but that's not the
    point)

    IMHO, modifying postsrsd looks like a much better alternative if I were
    to write something. Should be pretty easy to make it optionally use the sendmail socketmap protocol instead of the postfix tcp_table protocol.
    Or alternatively just write a simple proxy protocol translater. Then it
    could be plugged right into the example sendmail config from pysrs.

    But as have been the result each time I've considered SRS: I got bored
    with it long before I got it running. Why do I care whether google can
    send a bounce back? So I've just added owner-aliases for all my
    forwarded accounts (only a handful), pointing to a /dev/null address.

    That does it for me. SRS and SPF can continue to burn in the hell where
    it was invented.


    Stay tuned for the next episode of Mail Server Frustrations, where we'll
    look at Exim and mixed TLS (port 465) and STARTTLS (port 587) submission.



    Bjørn

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