Docker-mailserver: DKIM invalid signature

[rhyst]

Hey, sorry to trouble you with what is almost certainly a trivial error on my part. I am trying to get DKIM working on my domain but various mail test tools are reporting that the DKIM signature is invalid.

Context

I have the docker image up and running, and it sends emails and receives emails to a mailbox I added.
I generated a DKIM for the domain using ./setup.sh config dkim 2048. I used the key from the mail.txt in my DNS record as a txt record using the host mail._domainkey.

Expected Behavior

http://www.appmaildev.com/en/dkim/ should show DKIM as valid.

Actual Behavior

I get a bad signature error.

Your Environment

• Mailserver version used: latest
• Docker version used: 18.06.1-ce, build e68fc7a
• Environment settings relevant to the config:

The result of dig:

 dig TXT mail._domainkey.tyers.io

; <<>> DiG 9.11.3-1ubuntu1.1-Ubuntu <<>> TXT mail._domainkey.tyers.io
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42144
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;mail._domainkey.tyers.io.      IN      TXT

;; ANSWER SECTION:
mail._domainkey.tyers.io. 1417  IN      TXT     "v=DKIM1; h=sha256; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvSuw6Owc8H4Vpj3SXq9D+R4TYQnBYpr5hlpcQpc72W4MJPbYVu1av9d0zT9XY1io4b/CsjfHpFOlBSN/pQb8xkZ0NkLXehc8Bl3NkKgzVKRu5uu+EAszVsoEqrY3Glp6Bi+899mpY2MIrQCBaF+V+tEj0vVQlWyVvTvn5TyaQ2wTXP+1HN/pCK"

;; Query time: 0 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Mon Sep 17 10:55:02 UTC 2018
;; MSG SIZE  rcvd: 320

The contents of mail.txt

mail._domainkey IN      TXT     ( "v=DKIM1; h=sha256; k=rsa; "
          "p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvSuw6Owc8H4Vpj3SXq9D+R4TYQnBYpr5hlpcQpc72W4MJPbYVu1av9d0zT9XY1io4b/CsjfHpFOlBSN/pQb8xkZ0NkLXehc8Bl3NkKgzVKRu5uu+EAszVsoEqrY3Glp6Bi+899mpY2MIrQCBaF+V+tEj0vVQlWyVvTvn5TyaQ2wTXP+1HN/pCKVaha0yx/WVboGhnJpo6Vt0nL"
          "9bB80QdIKADohoPtIonBT7HCKG9pVx6jFOeAlmjD7851/V0mq4yFlXC9pMyMgqT2GJVvgRUt4ZqYDcCqiPJ+BQ6EUYCHBLVIe3EDugHnDPOQp4oURykg6lU7nPsJcE/PuQl47uRQIDAQAB" )  ; ----- DKIM key mail for tyers.io

The result of sending a message to my gmail:

Delivered-To: [email protected]
Received: by 2002:ac8:22fb:0:0:0:0:0 with SMTP id g56-v6csp1187737qta;
        Mon, 17 Sep 2018 03:57:50 -0700 (PDT)
X-Google-Smtp-Source: ANB0Vdb8DYDbfGV+NGlnYpjEeCfIzpAv5SiurOBm20tRE3azQBJBhYkOHKMNDbyyvQSrLOapjxEb
X-Received: by 2002:a50:c101:: with SMTP id l1-v6mr40709617edf.126.1537181870320;
        Mon, 17 Sep 2018 03:57:50 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; t=1537181870; cv=none;
        d=google.com; s=arc-20160816;
        b=JchUhXkGbaLb+exjiNFcA2DvXBEJEv1f2fArzjXMb137q9ttlUfEyP20y3Slmqx0e2
         K0nquJFQ/pe2/QjaYYaBdeIizb7AZMmwYMbYZ3SHrWZ/wZxYvRFrWRHNWPnXYb1Y1UTu
         MvQgXbRrNz3P0NkIUDQG/q9dRrbuPbQu6kzM+G3N/xaGCh/DCXY8rSkAOsWXg69W1MaL
         C23vIiZOuKDClS+fMZLdBEHM3pk+02BSTBtkv77IbBeZL+GHF1IRb5bX7uYhOK8Lqqv7
         LR6/pv+E4mFnwYPkUw1U4PtJicgyx6P8Zk7qDBXIRmIiz2NWBwvu6cFkxLdWyM1vBUYn
         j5Nw==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
        h=message-id:subject:date:from:dkim-signature;
        bh=kLtLHnbJqIFboEbJ18AcrQtf9rueliUl9sZzOhfCAME=;
        b=tUzrASHWfK1xEsMEX1tYImnqCiFWcTl8X5Okp+d31GzQ1WMKhrbDj6i/dsdq/6YrPN
         R5GR/VcRgWgc3bCkvVWLkTHvx3EFZIbYTyGLq08waPDXIdTT3oFd23Vj3ITROLmKr3m/
         VrS0Zl4cphZtTHjRTvO7J69+AW/S+VFlQl2718KIBticI/Vmi9DW636iKzcJTLkZgHxE
         w36LRwMlVHs7kvxM6/8LBfPAzuiZ+NerB06VCLBHXSZG1UyOPk41jhZWBCRnhvs5+Fwc
         FukkfWu/6KdFvz0u9T95NsjtMz9joty8UJB/cel8JhHeyMrZl68RHqR9j5hSfHwVtj3C
         J1Jg==
ARC-Authentication-Results: i=1; mx.google.com;
       dkim=neutral (invalid public key) [email protected] header.s=mail header.b=jcnp8bMb;
       spf=pass (google.com: domain of [email protected] designates 163.172.168.234 as permitted sender) [email protected]
Return-Path: <[email protected]>
Received: from mail.tyers.io (mail.tyers.io. [163.172.168.234])
        by mx.google.com with ESMTPS id o1-v6si983955edq.447.2018.09.17.03.57.49
        for <[email protected]>
        (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256);
        Mon, 17 Sep 2018 03:57:50 -0700 (PDT)
Received-SPF: pass (google.com: domain of [email protected] designates 163.172.168.234 as permitted sender) client-ip=163.172.168.234;
Authentication-Results: mx.google.com;
       dkim=neutral (invalid public key) [email protected] header.s=mail header.b=jcnp8bMb;
       spf=pass (google.com: domain of [email protected] designates 163.172.168.234 as permitted sender) [email protected]
X-Virus-Scanned: Yes
Received: from tyers.io (server [172.25.0.1]) by mail.tyers.io (Postfix) with SMTP id E7D27C8909 for <[email protected]>; Mon, 17 Sep 2018 10:57:48 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tyers.io; s=mail; t=1537181868; bh=kLtLHnbJqIFboEbJ18AcrQtf9rueliUl9sZzOhfCAME=; h=From:Subject; b=jcnp8bMb/MYF+AblGYe8lHshvEi3Qtm5Hdh0nko9GcV5p9hREyiwuEnHlnywEE8E8
     x7n1+PeG5E/EA9LoRRyVYKn8k/SFTSG+D2QINzbvnoT+vFuQG9V7d7/7ZVcuFvbfCe
     NcuWjd3BO4g3Y12XlIb9ffYunnzaSCjkjGC6wOKLAkC01J0feq6WrP3AiPkV2uzfVx
     QU0EjK/ff8KOBVQQy6sfvv+1j+DmHg+hvpqAz9AyoLXLcUIosSobuJdFG1lW6RVX2O
     ogtCi4GHcieuqwuA+NRAZV0zX3XTMNWNHPxrEW2cY7+Sm+iBwTwhwIA7Odg33la/qR
     a+iGlpRWRE67g==
Received: by tyers.io (sSMTP sendmail emulation); Mon, 17 Sep 2018 10:57:38 +0000
From: Rhys Tyers <[email protected]>
Date: Mon, 17 Sep 2018 10:57:38 +0000
Subject: Hello
Message-Id: <[email protected]>

Hello me

I saw from a different issue that I had to concatenate the string in mail.txt so I think I did that correctly. I also restarted the container after generating the DKIM key.

[rhyst]

DNS Provider did not support 2048 keys and was silently truncating the txt record. Ran./setup.sh config dkim 1024, replacedthe DNS records, and restarted the container and now it all works.