PODMAN DKIM Implementation Manual

This document provides complete technical and procedural guidance for deploying and maintaining a DomainKeys Identified Mail (DKIM) signing relay for GroupWise outbound email.

It enables authenticated, cryptographically signed outbound messages using domain-specific DKIM keys while relaying mail securely through the NO-IP SMTP service using SSL/TLS on port 465 (or directly as a standard MTA)

The environment uses Podman containers to encapsulate Postfix and OpenDKIM, providing isolation, reproducibility, and ease of backup.

Each domain is independently signed and routed using its own configuration, stored under /srv/dkim/<domain>.