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+# arcline-email — Todo
+
+## Phase 1: MVP (Core Mail Flow)
+
+### Project Setup
+- [ ] Initialize Go module (`go mod init arcline-email`)
+- [ ] Set up directory structure (`cmd/`, `internal/`, `config/`)
+- [ ] Add `.gitignore`
+- [ ] Wire up config parsing (TOML)
+- [ ] Structured logging (`log/slog`)
+- [ ] Graceful shutdown (signal handling)
+
+### SMTP — Inbound (Port 25)
+- [ ] Basic SMTP listener using `emersion/go-smtp`
+- [ ] Receive inbound mail for local domains
+- [ ] TLS support (STARTTLS)
+- [ ] Reject mail for unknown domains
+- [ ] Write received messages to Maildir
+
+### SMTP — Submission (Ports 587 / 465)
+- [ ] Authenticated submission listener
+- [ ] SASL PLAIN / LOGIN auth
+- [ ] Enforce auth before relaying
+- [ ] Outbound routing via MX DNS lookup
+- [ ] Delivery retry queue with backoff
+
+### IMAP (Ports 143 / 993)
+- [ ] IMAP server using `emersion/go-imap`
+- [ ] Authenticate users
+- [ ] Serve mailboxes from Maildir storage
+- [ ] Support INBOX, Sent, Drafts, Trash folders
+- [ ] IDLE command support
+
+### Storage
+- [ ] Maildir layout per user (`/var/mail/{domain}/{user}/`)
+- [ ] Message write (new mail delivery)
+- [ ] Message read / list / delete (for IMAP)
+- [ ] Quota tracking (basic)
+
+### Authentication
+- [ ] User store (flat file or SQLite — TBD)
+- [ ] Password hashing (bcrypt)
+- [ ] Domain and mailbox management (add/remove)
+
+### TLS
+- [ ] Load cert/key from disk
+- [ ] Auto-renew via ACME / Let's Encrypt (optional)
+
+---
+
+## Phase 2: Mail Hygiene
+
+- [ ] DKIM signing on outbound mail
+- [ ] DKIM verification on inbound mail
+- [ ] SPF record lookup and enforcement
+- [ ] DMARC policy parsing and enforcement
+- [ ] Reject or quarantine based on DMARC policy
+- [ ] DNSBL checks on inbound connections (basic blocklist)
+
+---
+
+## Phase 3: Admin & Operations
+
+- [ ] Admin HTTP API (manage domains, mailboxes, aliases)
+- [ ] Alias support (forward `info@` → real mailbox)
+- [ ] Catch-all address support
+- [ ] Metrics endpoint (Prometheus)
+- [ ] Log shipping / structured access logs
+- [ ] Systemd unit file
+
+---
+
+## Phase 4: Hardening
+
+- [ ] Rate limiting on SMTP connections
+- [ ] Connection-level blocklist (IP deny list)
+- [ ] Greylisting (optional)
+- [ ] rspamd milter integration (optional)
+- [ ] Deliverability testing (SPF/DKIM/DMARC pass verification)
+- [ ] Blacklist monitoring
+
+---
+
+## Stretch / Future
+
+- [ ] Webmail UI (separate project)
+- [ ] Multi-domain virtual hosting
+- [ ] Sieve filtering support
+- [ ] JMAP support