Load & use a dkim key file based on a header value, example : with header X-random-header: random-domain-2, zmta will use dkim key : /path/to/zone-mta/keys/random-domain-2.pem

Add this as a dependency for your ZoneMTA app (>= v2.3.0)

npm install @mindbaz/zonemta-multi-dkim --save

The module uses wild-config, so there are two toml configuration files to manage

Add a configuration entry in the "plugins" section of your ZoneMTA app

Example here.

ZoneMTA uses the following file for wild-config : /path/to/zone-mta/config/zonemta.toml

# Keys list, used to valid keys file name without extention .pem
[multi_dkim]
keys = [
  "random-domain-1",
  "random-domain-2",
  "random-domain-3"
]

The GNU General Public License 3 (details)