A four-container Docker stack that filters spam in any IMAP mailbox that supports IDLE. Designed to run 24/7 unattended on Unraid; never deletes mail, only IMAP MOVE.

GitHub: https://github.com/marcelverdult/imap-spamfilter

License: MIT

Image: ghcr.io/marcelverdult/imap-spamfilter:latest (linux/amd64, linux/arm64)

WHAT IT DOES

• Connects to each configured IMAP account via IDLE, scores incoming mail via rspamd (Bayes + RBL + SPF/DKIM/DMARC + neural)

• Three per-account modes promoted manually: shadow (log only) → flag (sets \Flagged) → move (relocates to Junk)

• Bayesian learning from explicit user actions:

- Move Inbox → Junk = learn as spam

- Move Junk → Inbox = learn as ham

- Copy known-good mail into Junk/Train-Ham = bulk ham training

- Drop spam into Junk/Train-Spam = bulk spam training

• Per-account Bayes namespaces, or pooled across mailboxes via shared bayes_user

• Rate-limited, self-recovering safe mode, auto-restarting account threads, exponential backoff

• Auto-detects junk/trash via RFC 6154 SPECIAL-USE, refuses to create core folders to avoid duplicate hierarchies

• SQLite WAL state DB with periodic pruning; weekly VACUUM

• Audit trail of every scan/move/learn decision in the events table

FOUR CONTAINERS

• spamfilter — the custom Python service (this repo)

• spamfilter-rspamd — rspamd/rspamd:latest, scoring + Bayes

• spamfilter-redis — redis:8-alpine, Bayes tokens + rate-limit state (AOF + RDB, capped 1 GB, noeviction)

• spamfilter-unbound — mvance/unbound:latest, local DNS resolver for RBLs (avoids upstream rate-limits)

All four communicate over a private spamnet docker network.

INSTALL (manual until CA accepts)

1. SSH into Unraid and run the bootstrap once to lay down appdata + the rspamd controller password:

curl -fsSL https://raw.githubusercontent.com/marcelverdult/imap-spamfilter/main/unraid/bootstrap.sh | bash

2. Docker tab → Add Container → paste each template URL below in turn. Apply.

https://raw.githubusercontent.com/marcelverdult/imap-spamfilter/main/unraid/spamfilter-redis.xml

https://raw.githubusercontent.com/marcelverdult/imap-spamfilter/main/unraid/spamfilter-unbound.xml

https://raw.githubusercontent.com/marcelverdult/imap-spamfilter/main/unraid/spamfilter-rspamd.xml

https://raw.githubusercontent.com/marcelverdult/imap-spamfilter/main/unraid/spamfilter.xml

3. Edit /mnt/user/appdata/spamfilter/accounts.yml with IMAP credentials.

4. Start spamfilter container.

REQUESTING CA INCLUSION

CA submission tracked at https://github.com/Squidly271/AppFeed/issues/31. Happy to address any feedback for inclusion.

KEY DOCS

• README: https://github.com/marcelverdult/imap-spamfilter#readme

• Folder discovery + manual override: README "Folder discovery and naming"

• Bayes pooling across accounts: README "Bayes identity"

• Backups: works with KluthR's Appdata Backup plugin

obviously i did something wrong!? how do i get this approved in the community apps?