pmeerw's blog

Fri, 26 Sep 2025

Easy DKIM/DMARC setup for multiple domains

It's possible to just list multiple domains in opendkim.conf which will all get signed with the same key indicated by KeyFile and Selector (as pointed out here).

# Sign for example.com with key in /etc/dkimkeys/dkim.key using
# selector 'mail' (e.g. mail._domainkey.example.com)
# hacky, multiple domains, all share the same key and the same DNS setup
# so we also need mail._domainkey.bla.net and mail._domainkey.blub.org DNS records
Domain                  example.com, bla.net, blub.org
KeyFile                 /etc/dkimkeys/example.com.key
Selector                mail

A more complex way with individual mappins is described here.

A good way to test the setup is appmaildev.com's DKIM Test.

posted at: 10:10 | path: /configuration | permanent link

Made with PyBlosxom