You may have read our blog post about ARC here

At the bottom of the post there are a number of resources listed:

For more information on ARC

ARC is not merely a protocol. There is a world of community support, and an ARC test suite (https://github.com/Valimail/arc_test_suite) that has proven useful in identifying specific issues and potential bugs to focus on at each interop. There are also numerous mature open source libraries that support ARC:


C: https://github.com/trusteddomainproject/OpenARC

Python: https://launchpad.net/dkimpy

Perl: https://metacpan.org/pod/Mail::DKIM

 

Since that article was posted, various mailing list software maintainers have updated their own documentation on supporting ARC and DMARC. 

For Mailmain-specific information see this link:

https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/handlers/docs/arc_sign.html