Stalwart Mail Server on Cloudron - Secure & Modern All-in-One Mail Server (IMAP, JMAP, POP3, SMTP)

[andreasdueren]

• Main Page: https://stalw.art/
• Git: https://github.com/stalwartlabs/mail-server
• Licence: AGPL v3 & SELv1 for some features
• Docker: Yes
• Documentation: https://stalw.art/docs/install/docker
• Demo: link

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• Summary: Stalwart Mail Server is an open-source mail server solution with SMTP, JMAP, IMAP4, and POP3 support and a wide range of modern features. It is written in Rust and aims to be secure, fast, robust and scalable.

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• Notes: Modern Mail server implementation with security features like Encryption at rest with S/MIME or OpenPGP

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Key features:

• JMAP, IMAP4, POP3 and ManageSieve server:
  • JMAP server with Sieve Scripts, WebSocket, Blob Management and Quotas extensions.
  • IMAP4rev2 and IMAP4rev1 server with support for numerous extensions.
  • POP3 server with extensions, STLS and SASL support.
  • ManageSieve server for managing Sieve scripts.
• SMTP server:
  • Built-in DMARC, DKIM, SPF and ARC support for message authentication.
  • Strong transport security through DANE, MTA-STS and SMTP TLS reporting.
  • Inbound throttling and filtering with granular configuration rules, sieve scripting, MTA hooks and milter integration.
  • Distributed virtual queues with delayed delivery, priority delivery, quotas, routing rules and throttling support.
  • Envelope rewriting and message modification.
• Built-in Spam and Phishing filter:
  • Comprehensive set of filtering rules on par with popular solutions.
  • LLM-driven spam filtering and message analysis.
  • Statistical spam classifier with automatic training capabilities.
  • DNS Blocklists (DNSBLs) checking of IP addresses, domains, and hashes.
  • Collaborative digest-based spam filtering with Pyzor.
  • Phishing protection against homographic URL attacks, sender spoofing and other techniques.
  • Trusted reply tracking to recognize and prioritize genuine e-mail replies.
  • Sender reputation monitoring by IP address, ASN, domain and email address.
  • Greylisting to temporarily defer unknown senders.
  • Spam traps to set up decoy email addresses that catch and analyze spam.
• Flexible and scalable:
  • Pluggable storage backends with RocksDB, FoundationDB, PostgreSQL, mySQL, SQLite, S3-Compatible, Redis and ElasticSearch support.
  • Clustering support with node autodiscovery and partition-tolerant failure detection.
  • Full-text search available in 17 languages.
  • Sieve scripting language with support for all registered extensions.
  • Email aliases, mailing lists, subaddressing and catch-all addresses support.
  • Automatic account configuration and discovery with autoconfig and autodiscover.
  • Multi-tenancy support with domain and tenant isolation.
  • Disk quotas per user and tenant.
• Secure and robust:
  • Encryption at rest with S/MIME or OpenPGP.
  • Automatic TLS certificate provisioning with ACME using TLS-ALPN-01, DNS-01 or HTTP-01 challenges.
  • Automated blocking of IP addresses that attack, abuse or scan the server for exploits.
  • Rate limiting.
  • Security audited (read the report).
  • Memory safe (thanks to Rust).
• Authentication and Authorization:
  • OpenID Connect authentication.
  • OAuth 2.0 authorization with authorization code and device authorization flows.
  • LDAP, OIDC, SQL or built-in authentication backend support.
  • Two-factor authentication with Time-based One-Time Passwords (2FA-TOTP)
  • Application passwords (App Passwords).
  • Roles and permissions.
  • Access Control Lists (ACLs).
• Observability:
  • Logging and tracing with OpenTelemetry, journald, log files and console support.
  • Metrics with OpenTelemetry and Prometheus integration.
  • Webhooks for event-driven automation.
  • Alerts with email and webhook notifications.
  • Live tracing and metrics.
• Web-based administration:
  • Dashboard with real-time statistics and monitoring.
  • Account, domain, group and mailing list management.
  • SMTP queue management for messages and outbound DMARC and TLS reports.
  • Report visualization interface for received DMARC, TLS-RPT and Failure (ARF) reports.
  • Configuration of every aspect of the mail server.
  • Log viewer with search and filtering capabilities.
  • Self-service portal for password reset and encryption-at-rest key management.

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• Screenshots:

[andreasdueren]

I spun up a test instance and it looks really polished and fast. I'm not a developer but seems to be fairly simple with few dependencies. Written in rust, PostgreSQL support.

Absolute extensive feature list, including encryption at rest, E-Mail delivery debugging, telemetry and much more.

Most if not all things can be configured in the GUI after setup. The biggest Problem at that point really is locking down the server against improper use, which is something cloudron already does pretty well. I'd love to see this in the App Store.

[andreasdueren]

@nebulon Is there a way to set this up besides the cloudron E-Mail server? What ports could I map this to if I wanted to test package this for cloudron?
I was thinking of

IMAP: 1143 (with TLS) for a balance of simplicity and firewall compatibility. Alternatively, a high port like 50000.

SMTP: 2525 (with STARTTLS) as it’s widely supported and rarely blocked. Alternatively 2587 or a high port like 55000.

[necrevistonnezr]

I believe all used ports are listed here: https://docs.cloudron.io/security/#cloud-firewall
Does that help?

[andreasdueren]

@necrevistonnezr Yes I've seen those, just wanted to know if there were any other considerations from the devs