Implementing DKIM in UCS does not work

Hello everyone,

I have tried to implement DKIM in my mail server (for according to the detailed instructions:

I use UCS V 8.09 / Kopano Version 5.0-5.

If I test the implementation with:

opendkim-testkey -d -s mail -vvv

everything seems to work:

opendkim-testkey: using default configfile /etc/opendkim.conf
opendkim-testkey: checking key ‘’
opendkim-testkey: key not secure
opendkim-testkey: key OK

In postfix the required options are also set:

milter_default_action = accept
milter_protocol = 6
smtpd_milters = inet:localhost:12301
non_smtpd_milters = inet:localhost:12301

I have also entered the public DKIM key on my DNS server, the test on “Check a DKIM Core Key” showed: “This is a valid DKIM key record”

I completely restarted the server, so everything seems to be ok.

But when I test my implementation on

I get the information that my mail does not contain a DKIM key:

DKIM Information:

DKIM Signature

This message does not contain a DKIM Signature

I checked everything multiple times and can’t find an error. What am I doing wrong, have I forgotten something?

I would be very grateful for any tips on how to proceed.

Best regards,


Hello everyone,

I have just been able to solve the problem by myself. In the instructions on:

the DKIM configuration in the file “/etc/default/opendkim” is edited. This does not work in my case. However, if I copy the entries there into the file “/etc/default/opendkim”, it now works.