• Community Support
  • USEnglish

  • encoding from different mail clients using mailcow as mail server

Have something to say?

Join the community by quickly registering to participate in this discussion. We'd like to see you joining our great moo-community!

@esackbauer

Could you tell me where exactly are the dkim keys in mailcow stored? Files or database? And I’d like to know how to get there.

More testing with emails to a vodafone account:

mx5.vodafonemail.de/4SV90B37Vyz9ryY;
dkim=fail reason=“signature verification failed” (2048-bit key; unprotected) header.d=x.de header.i=@x.de header.a=rsa-sha256 header.s=dkim header.b=cVJitv3G;
dkim-atps=neutral

I did a diff -s file1 <– dkim from mailcow file2 <– dkim copied to DNS. They are identical.

Could it be, that if restoring a mailcow backup, the keys are messed up? I’d like to check the keys (public and private) before restore and after restore.

    stefan21 Could it be, that if restoring a mailcow backup, the keys are messed up?

    That could be. Probably they are stored in the Redis DB. I remember a thread in this forum where they discussed problems with the DKIM keys.

      Well, I’d like to check this. What’s the best approach to access the DB?

      BTW here’s the email to the vodafone account:

      "
      test
      –=20
      Mit freundlichen Gr=C3=BC=C3=9Fen,

      Mit freundlichen Gr=C3=BC=C3=9Fen,

      =C3=B6=C3=A4=C3=BC=C3=9F

      "

      Umlaute in signature and domain footer… as already seen. Of course with a failed dkim key after a restore. To verify the suspicion I’ll wipe/delete the mailcow install on my laptop and start over with a new, clean install. No restores, no imports, nothing. Means from scratch. Will report.

        stefan21
        Now I am thinking that the Umlaute conversion is the reason why the DKIM fails. Something is changing the character encoding in transit and changing the “checksum”. Maybe the DKIM keys are fine.

        I never tried to access the Redis DB, don’t know.

            esackbauer Now I am thinking that the Umlaute conversion is the reason why the DKIM fails. Something is changing the character encoding in transit and changing the “checksum”.

            Let me start over with a fresh clean install. I’ll create a domain (same I use for tests), a user, will copy the new dkim key to DNS, nothing more. I’ll do a “vanilla” backup. First email will be with no umlaute. Second email will have umlaute. Third email will have signature and Umlaute. Forth one will have the signature and a system wide footer with umlaute.

            I’ll report.

              I did the tests. Here are the results:

              1. Sending an email from SOGO in HTML format, no matter what language, with signature and footer, with german umlaute, works correct. The dkim test pass:
                mx5.vodafonemail.de/4SVGtc1n9xz9rxk;
                dkim=pass (2048-bit key; unprotected) header.d=y.de header.i=@y.de header.a=rsa-sha256 header.s=dkim header.b=An7pjvp1;
                dkim-atps=neutral

              2. Sending an email from SOGO in plain text format, no matter what language, with signature and footer, with german umlaute, will not work. The dkim test fails.
                mx5.vodafonemail.de/4SVH2f6TNFz6vhw;
                dkim=fail reason=“signature verification failed” (2048-bit key; unprotected) header.d=y.de header.i=@y.de header.a=rsa-sha256 header.s=dkim header.b=QWmUDGNz;
                dkim-atps=neutral

              Reverting in SOGO back to html text will pass the dkim test (again).

              1. Sending an email form email-client thunderbird in HTML format, no matter what language, with signature and footer, with german umlaute, will not work. dkim test fails. The layout of the email looks like:
                "
                umlaute: =C3=B6=C3=A4=C3=BC=C3=9F

              –=20
              Mit freundlichen Gr=C3=BC=C3=9Fen,

              1. Sending emails from thunderbird will always fail the dkim test. No matter if plain text or html.

              To resume:

              • sending emails from SOGO in html containing german umlaute, works. DKIM will pass.
              • sending emails from SOGO in plain text containing german umlaute leads to DKIM fails.
              • sending emails from email-client thunderbird will always fail the dkim test. And the german umlaute are in a wrong format.

              As we need thunderbird out of several reasons, at this moment with the results above, I cannot migrate my email servers to mailcow. We send, and will this probably do also in future, emails only in plain text format. And we need dkim, dmarc and spf - valid.

              Besides the question of restoring a backup to different box with another underlying OS and the decryption of the emails, while doing a restore of all items including the keys. But this point for the moment is less important, it could be solved in another way.

              How to proceed?

              Can’t tell. Sending emails composed in sogo with plain text and umlaute to i.e. domain hosted at allinkl brings up the same result:

              Authentication-Results: q.kasserver.com;
              dkim=fail reason=“signature verification failed” (2048-bit key; unprotected) header.d=x.de header.i=@x.de header.a=rsa-sha256 header.s=dkim header.b=JevnIlCW;
              dkim-atps=neutral

              I’m sending from a socalled pool IP: IP-x.x.x.x-um38.pools.vodafone-ip.de. Means not a static IP. But if this causes the failure, then the failure should also be while sending in HTML. As I pointed out, DKIM passes with email sent from the same (dynamic) IP(4).

              IMVHO I don’t think so.

                stefan21 OK, according to your header examples from above it was always mx5.vodafonemail.de which had the problem with your DKIM, so I thought it’s Vodafone specific.
                But, as I wrote above, no DKIM problems here sending plaintext mails with Sogo

                  @DocFraggle

                  If you like, you could tell me one of your email adresses (is in this forum a pm function?). I’ll send you an email. Let’s see how this works.

                  Well, since yesterday I have one user who also has encoding troubles. User is on iPad with ActiveSync configured. User can send via SOGo without problems, but from Apples integrated mail client outgoing mails are totally unreadable.
                  Had no time to investigate further yet.

                    esackbauer OK, I just checked this on my iPad and my ActiveSync account, works as usual with iPadOS 16.7.2 and after updating to iPadOS 17.1.1 in my case

                      Have deleted and reinstalled the Activesync account with my Ipad user. Problem persists. But only with that iPad user.
                      Installed the mobileconfig IMAP profile and everything as back to normal.

                      DocFraggle
                      @esackbauer

                      Here’s the result from the dkimvalidator:

                      #######
                      Original Message:

                      Received: from mail.z.de (ip-109-192-q-q.um38.pools.vodafone-ip.de [109.192.q.q])
                      by relay-1.us-west-2.relay-prod (Postfix) with ESMTPS id BB5E628E53
                      for RO3ER2LYBB7X5n@dkimvalidator.com; Fri, 17 Nov 2023 11:44:00 +0000 (UTC)
                      Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPA id 203793C009C
                      for RO3ER2LYBB7X5n@dkimvalidator.com; Fri, 17 Nov 2023 12:43:54 +0100 (CET)
                      DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=z.de; s=dkim;
                      t=1700221435;
                      h=from:reply-to:subject:date:message-id:to:mime-version:content-type:
                      content-transfer-encoding; bh=lZj4ZrwRyEiLyclvgIilptURN6KHsH85iH83mFdpfT0=;
                      b=WOezYpMCyhYml9qghfu2Iikoe9pM7Rbdk1G3L0aTEsLcknLE13xr2kza07cc6y+/cQTBDz
                      vLwzHs2pUqdohgDrFvuvUnGzKa8SD/3rLDDImyor37oWIYCe2f/GTjr6H18Gfq3mzOc/wq
                      Fd45OF0rbl/ACT7bmNfpWFOuBLyIpdhadysT6ggYT+dSaXYrFDTnCGC/Ux4tYaD+Uuy/r2
                      A09tU6tqTNFCk3OKc6QdelA1D5663ZQI9y58nF1v8MZ2BCl1MgtaPdaEmPQKFsjNeR9plG
                      GBokcfLamSFqHDajTTphfw4QGAWMC4RavRs508MPfd5Hl0YFhjobYFZ7xbsLug==
                      From: “X Y” x.y@z.de
                      Content-Type: text/plain; charset=“utf-8”
                      Reply-To: x.y@z.de
                      Date: Fri, 17 Nov 2023 12:43:54 +0100
                      To: RO3ER2LYBB7X5n@dkimvalidator.com
                      MIME-Version: 1.0
                      Message-ID: <42-65575200-3-560d3d80@48021463>
                      Subject: =?utf-8?q?T=C3=84SCHT?=
                      User-Agent: SOGoMail 5.9.0
                      Content-Transfer-Encoding: quoted-printable
                      X-Last-TLS-Session-Version: None

                      Sogo, plain text, signatur mit umlauten, footer mit umlauten

                      –=20
                      signature

                      plain text
                      =C3=B6=C3=A4=C3=BC=C3=9F

                      plain footer
                      =C3=B6=C3=A4=C3=BC=C3=9F

                      #######
                      DKIM Information:

                      DKIM Signature

                      Message contains this DKIM Signature:
                      DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=z.de; s=dkim;
                      t=1700221435;
                      h=from:reply-to:subject:date:message-id:to:mime-version:content-type:
                      content-transfer-encoding; bh=lZj4ZrwRyEiLyclvgIilptURN6KHsH85iH83mFdpfT0=;
                      b=WOezYpMCyhYml9qghfu2Iikoe9pM7Rbdk1G3L0aTEsLcknLE13xr2kza07cc6y+/cQTBDz
                      vLwzHs2pUqdohgDrFvuvUnGzKa8SD/3rLDDImyor37oWIYCe2f/GTjr6H18Gfq3mzOc/wq
                      Fd45OF0rbl/ACT7bmNfpWFOuBLyIpdhadysT6ggYT+dSaXYrFDTnCGC/Ux4tYaD+Uuy/r2
                      A09tU6tqTNFCk3OKc6QdelA1D5663ZQI9y58nF1v8MZ2BCl1MgtaPdaEmPQKFsjNeR9plG
                      GBokcfLamSFqHDajTTphfw4QGAWMC4RavRs508MPfd5Hl0YFhjobYFZ7xbsLug==

                      Signature Information:
                      v= Version: 1
                      a= Algorithm: rsa-sha256
                      c= Method: relaxed/relaxed
                      d= Domain: z.de
                      s= Selector: dkim
                      q= Protocol:
                      bh= lZj4ZrwRyEiLyclvgIilptURN6KHsH85iH83mFdpfT0=
                      h= Signed Headers: from:reply-to:subject:date:message-id:to:mime-version:content-type:
                      content-transfer-encoding
                      b= Data: WOezYpMCyhYml9qghfu2Iikoe9pM7Rbdk1G3L0aTEsLcknLE13xr2kza07cc6y+/cQTBDz
                      vLwzHs2pUqdohgDrFvuvUnGzKa8SD/3rLDDImyor37oWIYCe2f/GTjr6H18Gfq3mzOc/wq
                      Fd45OF0rbl/ACT7bmNfpWFOuBLyIpdhadysT6ggYT+dSaXYrFDTnCGC/Ux4tYaD+Uuy/r2
                      A09tU6tqTNFCk3OKc6QdelA1D5663ZQI9y58nF1v8MZ2BCl1MgtaPdaEmPQKFsjNeR9plG
                      GBokcfLamSFqHDajTTphfw4QGAWMC4RavRs508MPfd5Hl0YFhjobYFZ7xbsLug==
                      Public Key DNS Lookup

                      Building DNS Query for dkim._domainkey.z.de
                      Retrieved this publickey from DNS: v=DKIM1;k=rsa;t=s;s=email;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtHkJ1zfpaCrbEr5y4riJc82jyNtNheQrREUuH1dhKOwfhyIeqHtAWPir5sdkn418FJ8j4Zu1N7g0xqQqvceXwllO2xik+tLAsWMYk2t7XvD7IWM9D1awaC9QgTPXk7v9mGEjh1HSvrxyBr7Fa8cJP56Ujhda7xpCw05AZTJL7Nu3hgnc6dEAotF1qEIpof6XJ5XW0zzd3cxvyN5TE12ewSYE6GblgtQjTNYyGaW2l4o8Kxpw6Qha1XowoDq/Eyv2PFyPbUg8i3QXLxBaGJQ0U+j8Tk0T1iay1AukZAdCvnPa8UCrc9CkKQ73TG+nd9OL4zZdwSVWWYTV8MzjwgABowIDAQAB
                      Validating Signature

                      result = fail
                      Details: message has been altered

                      #######
                      SPF Information:

                      Using this information that I obtained from the headers

                      Helo Address = mail.z.de
                      From Address = x.x@z.de
                      From IP = 109.192.q.q
                      SPF Record Lookup

                      Looking up TXT SPF record for z.de
                      Found the following namesevers for z.de: ns5.kasserver.com ns6.kasserver.com
                      Retrieved this SPF Record: zone updated 20210630 (TTL = 167)
                      using authoritative server (ns5.kasserver.com) directly for SPF Check
                      Result: pass (Mechanism ‘mx’ matched)

                      Result code: pass
                      Local Explanation: z.de: 109.192.q.q is authorized to use ‘x.y@z.de’ in ‘mfrom’ identity (mechanism ‘mx’ matched)
                      spf_header = Received-SPF: pass (z.de: 109.192.q.q is authorized to use ‘x.y@z.de’ in ‘mfrom’ identity (mechanism ‘mx’ matched)) receiver=ip-172-31-52-154.ec2.internal; identity=mailfrom; envelope-from=“x.y@z.de”; helo=mail.z.de; client-ip=109.192.q.q

                      Same test, but as html text in sogo:

                      #######
                      From: “x y” x.y@z.de
                      Content-Type: multipart/alternative; boundary=“—-==-OpenGroupware_org_NGMime-65-1700222345.461701-0——”
                      Reply-To: x.y@z.de
                      Date: Fri, 17 Nov 2023 12:59:05 +0100
                      To: iBsUWO3nrKugbZ@dkimvalidator.com
                      MIME-Version: 1.0
                      Message-ID: <41-65575580-5-677bcc00@203231989>
                      Subject: =?utf-8?q?T=C3=84SCHT?=
                      User-Agent: SOGoMail 5.9.0
                      X-Last-TLS-Session-Version: None

                      ——==-OpenGroupware_org_NGMime-65-1700222345.461701-0——
                      Content-Type: text/plain; charset=utf-8
                      Content-Transfer-Encoding: quoted-printable

                      Sogo, html text, signatur mit umlauten, footer mit umlauten

                      –=C2=A0
                      signature plain text =C3=B6=C3=A4=C3=BC=C3=9F

                      plain footer
                      =C3=B6=C3=A4=C3=BC=C3=9F

                      ——==-OpenGroupware_org_NGMime-65-1700222345.461701-0——
                      Content-Type: text/html; charset=utf-8
                      Content-Transfer-Encoding: quoted-printable

                      <html>Sogo, html text, signatur mit umlauten, footer mit umlauten<br /><br />–=
                      &nbsp;<br />signature plain text =C3=B6=C3=A4=C3=BC=C3=9F</html>

                      html footer
                      =C3=B6=C3=A4=C3=BC=C3=9F

                      ——==-OpenGroupware_org_NGMime-65-1700222345.461701-0——–

                      #######
                      Public Key DNS Lookup

                      Building DNS Query for dkim._domainkey.z.de
                      Retrieved this publickey from DNS: v=DKIM1;k=rsa;t=s;s=email;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtHkJ1zfpaCrbEr5y4riJc82jyNtNheQrREUuH1dhKOwfhyIeqHtAWPir5sdkn418FJ8j4Zu1N7g0xqQqvceXwllO2xik+tLAsWMYk2t7XvD7IWM9D1awaC9QgTPXk7v9mGEjh1HSvrxyBr7Fa8cJP56Ujhda7xpCw05AZTJL7Nu3hgnc6dEAotF1qEIpof6XJ5XW0zzd3cxvyN5TE12ewSYE6GblgtQjTNYyGaW2l4o8Kxpw6Qha1XowoDq/Eyv2PFyPbUg8i3QXLxBaGJQ0U+j8Tk0T1iay1AukZAdCvnPa8UCrc9CkKQ73TG+nd9OL4zZdwSVWWYTV8MzjwgABowIDAQAB
                      Validating Signature

                      result = pass
                      Details:

                      But - bad format with umlaute.

                      Anyway - we need as email-client thunderbird.

                      As I already wrote, if it helps I have other linux mailservers in my LAN(s) (also with sogo, not used), I can provide configs and versions. The used programs are AFAIK pretty much the same.

                      If there’s interest to track this down, I’d suggest to do this not in this forum. It’s better done via email.

                        Details: message has been altered

                        Strange, is there anything in-between your mailcow and your local gateway to the internet?
                        The validator had no problems on my side with plain text Umlaut mails from Sogo…

                          DocFraggle trange, is there anything in-between your mailcow and your local gateway to the internet

                          That is also my suspicion. Some transparent filters on the firewall I would guess.

                            O.k. thank’s for sharing your thoughts.

                            I’ll check/disable in case anything on my asus home router, and will test again. I’ll be back.

                            I disabled diversion and skynet, the router DNS is unbound.

                            DKIM passes, encoding/format is faulty:

                            Date: Fri, 17 Nov 2023 14:32:31 +0100
                            To: djrEXr4DjZ2CAP@dkimvalidator.com
                            MIME-Version: 1.0
                            Message-ID: <41-65576b80-d-677bcc00@203232121>
                            Subject: =?utf-8?q?T=C3=84SCHT?=
                            User-Agent: SOGoMail 5.9.0
                            X-Last-TLS-Session-Version: None

                            ——==-OpenGroupware_org_NGMime-65-1700227951.204159-2——
                            Content-Type: text/plain; charset=utf-8
                            Content-Transfer-Encoding: quoted-printable

                            sogo html text, signatur and footer mit umlaute
                            =C3=A4=C3=B6=C3=BC=C3=9F

                            –=C2=A0
                            signature plain text =C3=B6=C3=A4=C3=BC=C3=9F

                            plain footer
                            =C3=B6=C3=A4=C3=BC=C3=9F

                            ——==-OpenGroupware_org_NGMime-65-1700227951.204159-2——
                            Content-Type: text/html; charset=utf-8
                            Content-Transfer-Encoding: quoted-printable

                            <html>sogo html text, signatur and footer mit umlaute<br />=C3=A4=C3=B6=C3=BC=
                            =C3=9F<br /><br />–&nbsp;<br />signature plain text =C3=B6=C3=A4=C3=BC=C3=9F</=
                            html>

                            html footer
                            =C3=B6=C3=A4=C3=BC=C3=9F

                            ——==-OpenGroupware_org_NGMime-65-1700227951.204159-2——–

                            What is this ——==-OpenGroupware_org_NGMime-65-1700227951.204159-2——– about?