DKIM signature and hmailserver – Your DKIM signature is not valid

dkim

I'm trying to get DKIM working on a domain using hmailserver as the mailserver, but I keep on getting Your DKIM signature is not valid

This is from www.mail-tester.com

The DKIM signature of your message is:

v=1;
a=rsa-sha256;
d=twitterautopost.co.uk;
s=key1;
c=simple/simple;
q=dns/txt;
h=From:Subject:Date:Message-ID:To:MIME-Version:Content-Type:Content-Transfer-Encoding;
bh=UmH1WrduLl3abcMsoAbrWmKA9BGd7W0M4NcX7EZqo/s=;
b=ibp5puhoKfSAeV4GUxCAV+YQd25s2/GiBA7k7dFmSSIjpcwIyau54545SdTRmF8yLDCrVCkll+fa2VERESLpNWDnYyQXrW+BjhSTRcDOnYYKTCghkbNc4FaspEdRvuMzzL1OeQ7LFsrp9HJ6N0NheRIyDQAG4hFM=

Your public key is:

"k=rsa\\;
p=MIGfMA0GCSqGSIb3DQEBAQUAA4G6WPaESxPzkXT1jsC+ivorJij0gXi39XlBFJfB1/M+quGClJPNquvJAeEWZ7SOQI7pRPcvnwySapJMfjIlH7n23F4eDwkJO8lEvC5HhTM13Ecz5QVe+/jM8jUgGjuF57NsCmPXMXw6TAKcFUyNcK6plnfsRyzgBbGLZr2ishWZQIDAQAB"
Key length: 1024bits

Your DKIM signature is not valid

(I removed some characters from the keys)

I have made a TXT entry into the domains DNS as follows :

key1._domainkey.twitterautopost.co.uk = k=rsa\; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDM6WPaESxPzkXT1jsC+ivorJij0gXi39XlBFJfB1/M+quGClJPNquvJAeEWZ7SOQI7pRPcv3F4eDwkJO8lEvC5HhTM13Ecz5QVe+/jM8jUgGjuF57NsCmPXMXw6TAKcFUyNcK6plnfsRyzgBbGLZr2ishWZQIDAQAB

Not sure what to try now.

Any help would be greatly appreciated. Thanks.

Best Answer

The key doesn't seem to be RSA public key.

I see the latest record that exists on key1._domainkey.twitterautopost.co.uk is validated correctly.

Related Solutions

Centos – Outbound emails not being signed with DKIM using Postfix on Centos

You need to add opendkim as a milter to postfix.

Make sure these two lines are in postfix's main.cf:

milter_protocol = 2
milter_default_action = accept

Then add opendkim to your milters:

smtpd_milters = inet:localhost:8891
non_smtpd_milters = inet:localhost:8891

I would also add localhost to the TrustedHosts file for opendkim since it's possible that postfix will connect to it over IPv6 (::1) instead of IPv4 (127.0.0.1). Having localhost in the TrustedHosts file should be sufficient.

See: https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-dkim-with-postfix-on-debian-wheezy for some more details.

Debian – DKIM header exists but signature is not valid

Now the validator at mail-tester.com says the DKIM signature is fine. On the other hand the isnotspam.com still doesn't seem to like it. I assume it is working fine now. Also gmail accepts the email.

The change I made:

I changed the smtpd_tls_cert_file=.. smtpd_tls_key_file=..

to hold the keys for the primary domain. However my VPS contains several domains, so it still remains to be seen what happens with mails from

someone@example2.com

First the postfix SSL certs have absolutely nothing to do with DKIM so that was different issue you had.

Second if you still are getting errors at isnotspam.com then don't assume everything is alright until you get a green light on all tests.

Third create new signatures for each domain and make sure the DNS entry is correct as well as permissions on the signature files.

Also make sure your postfix/main.cf has the proper entries and the .sock actually exists.

    # DKIM / SPF
# --------------------------------------
milter_default_action = accept
milter_protocol = 6
smtpd_milters = unix:/var/run/opendkim/opendkim.sock
non_smtpd_milters = $smtpd_milters

Check mail logs for errors, warnings after restart opendkim, should look something like this:

Feb 21 17:18:23 serverdcu opendkim[2078]: OpenDKIM Filter: mi_stop=1
Feb 21 17:18:23 serverdcu opendkim[2078]: OpenDKIM Filter v2.11.0 terminating with status 0, errno = 0
Feb 21 17:18:23 serverdcu opendkim[37449]: OpenDKIM Filter v2.11.0 starting (args: -P /var/run/opendkim/opendkim.pid -p local:/var/run/opendkim/opendkim.sock)

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