Overview

You want to enable DKIM for 2 servers in the same domain, where you can have one server forwarding some emails to another server with the same base domain. This helps prevents emails from getting incorrectly blocked.

Solution

In order to understand the solution steps, we will consider 2 Kerio Connect mail servers mail1.domain.com and mail2.domain.com, where mail1 will be forwarding emails to mail2.

Access to Kerio Connect administration is required for both the servers for the below steps:

1. Setup a DKIM record for the mail1.domain.com server as explained in the Adding a DKIM Record to Your DNS section of the Configuring DNS for DKIM in Kerio Connect article. Only the steps outlined in this section need to be followed.
2. Verify that DKIM is working correctly for mail1.domain.com.
3. On the mail1.domain.com server, go to the Kerio Connect dkim directory. Below are the default locations:

Windows: C:\Program Files\Kerio\MailServer\sslcert\dkim\
Linux: /opt/kerio/mailserver/sslcert/dkim/
macOS: /usr/loca/kerio/mailserver/sslcert/dkim/

4. Copy the contents of the private.key file.
5. Go to mail2.domain.com and stop the Kerio Connect service (Windows, macOS/Linux).
6. On the mail2.domain.com server, go to the same dkim directory.
7. Copy it's private.key file to another location on the server.
8. Replace the contents of the private.key file on the mail2.domain.com server with the contents of the private.key file from the mail1.domain.com server (from step 4 above).
9. Start the Kerio Connect service on mail2.domain.com (Windows, macOS/Linux).

Testing

Verify that you are now able to forward emails from mail1.domain.com to mail2.domain.com and they are not blocked.

In the case there are issues with mail forwarding, open a Support request with us.