Block a user
SPF record lookup and enforcement
DKIM verification on inbound mail
DKIM signing on outbound mail
Auto-renew via ACME / Let's Encrypt (optional)
Domain and mailbox management (add/remove)
User store (flat file or SQLite — TBD)
Message read / list / delete (for IMAP)
Message write (new mail delivery)
Maildir layout per user (
/var/mail/{domain}/{user}/)
Support INBOX, Sent, Drafts, Trash folders
Serve mailboxes from Maildir storage
IMAP server using
emersion/go-imap
Delivery retry queue with backoff
Outbound routing via MX DNS lookup