My old DKIM key was only 1024 bits so I updated it to 2048. I went through all the step correctly and the system generated a new key. I used a different selector in the process.
I use external DNS and updated it accordingly. This was done a couple months ago.
For some reason the system is signing messages using the old selector and 1024 bit key. Anyone got any ideas?
Ok so I checked the config file for DKIM
/etc/opendkim.conf
The selector is set to the new value - it’s “2017”
The old one is “2012” and for some reason that’s what is being used on outgoing e-mail for every domain. All of these domains are set to use the global default key (2017 selector).
Apologies for the necro but I just had this issue in the current version of Webmin [1.900] where changing selector is not updated in /etc/dkim-keytable.
After changing it manually and restarting opendkim with sudo service opendkim restart the correct selector is now being specified and my email is working correctly.