mail-server/README.md

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<h3 align="center">
  Secure & Modern All-in-One Mail Server (IMAP, JMAP, POP3, SMTP) 🛡️
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<br>

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## Features

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

Key features:

- **JMAP** server:
  - [JMAP Core](https://datatracker.ietf.org/doc/html/rfc8620) and [JMAP Mail](https://datatracker.ietf.org/doc/html/rfc8621) full compliance.
  - [JMAP for Sieve Scripts](https://www.ietf.org/archive/id/draft-ietf-jmap-sieve-22.html) extension for managing Sieve scripts.
  - [JMAP for WebSocket](https://datatracker.ietf.org/doc/html/rfc8887), [JMAP Blob Management](https://www.rfc-editor.org/rfc/rfc9404.html) and [JMAP for Quotas](https://www.rfc-editor.org/rfc/rfc9425.html) extensions.
- **IMAP4**, **POP3** and **ManageSieve** server:
  - [IMAP4rev2](https://datatracker.ietf.org/doc/html/rfc9051) and [IMAP4rev1](https://datatracker.ietf.org/doc/html/rfc3501) server with support for [numerous extensions](https://stalw.art/docs/development/rfcs#imap4-and-extensions).
  - [POP3](https://datatracker.ietf.org/doc/html/rfc1939) server with [extensions](https://datatracker.ietf.org/doc/html/rfc2449), [STLS](https://datatracker.ietf.org/doc/html/rfc2595) and [SASL](https://datatracker.ietf.org/doc/html/rfc5034) support.
  - [ManageSieve](https://datatracker.ietf.org/doc/html/rfc5804) server for managing Sieve scripts.
- **SMTP** server:
  - Built-in [DMARC](https://datatracker.ietf.org/doc/html/rfc7489), [DKIM](https://datatracker.ietf.org/doc/html/rfc6376), [SPF](https://datatracker.ietf.org/doc/html/rfc7208) and [ARC](https://datatracker.ietf.org/doc/html/rfc8617) support for message authentication.
  - Strong transport security through [DANE](https://datatracker.ietf.org/doc/html/rfc6698), [MTA-STS](https://datatracker.ietf.org/doc/html/rfc8461) and [SMTP TLS](https://datatracker.ietf.org/doc/html/rfc8460) reporting.
  - Inbound throttling and filtering with granular configuration rules, sieve scripting and milter integration.
  - Distributed virtual queues with delayed delivery, priority delivery, quotas, routing rules and throttling support.
  - Envelope rewriting and message modification.
- **Spam Phishing** filter:
  - Comprehensive set of filtering **rules** on par with popular solutions.
  - 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.
  - Built-in, **LDAP** or **SQL** authentication backend support.
  - Full-text search available in 17 languages.
  - Sieve scripting language with support for all [registered extensions](https://www.iana.org/assignments/sieve-extensions/sieve-extensions.xhtml).
  - Email aliases, mailing lists, subaddressing and catch-all addresses support.
  - Automatic account configuration and discovery with [autoconfig](https://www.ietf.org/id/draft-bucksch-autoconfig-02.html) and [autodiscover](https://learn.microsoft.com/en-us/exchange/architecture/client-access/autodiscover?view=exchserver-2019). 
  - Integration with **OpenTelemetry** to enable monitoring, tracing, and performance analysis.
  - Disk quotas.
- **Web-based administration**:
  - 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.
- **Secure and robust**:
  - Encryption at rest with **S/MIME** or **OpenPGP**.
  - Automatic TLS certificate provisioning with [ACME](https://datatracker.ietf.org/doc/html/rfc8555) using `TLS-ALPN-01`, `DNS-01` or `HTTP-01` challenges.
  - OAuth 2.0 [authorization code](https://www.rfc-editor.org/rfc/rfc8628) and [device authorization](https://www.rfc-editor.org/rfc/rfc8628) flows.
  - Automated blocking of hosts that cause multiple authentication errors (aka **fail2ban**).
  - Access Control Lists (ACLs).
  - Rate limiting.
  - Security audited (read the [report](https://stalw.art/blog/security-audit)).
  - Memory safe (thanks to Rust).

## Screenshots

<img src="./img/screencast-setup.gif">

## Get Started

Install Stalwart Mail Server on your server by following the instructions for your platform:

- [Linux / MacOS](https://stalw.art/docs/install/linux)
- [Windows](https://stalw.art/docs/install/windows)
- [Docker](https://stalw.art/docs/install/docker)

All documentation is available at [stalw.art/docs/get-started](https://stalw.art/docs/get-started).

## Support

If you are having problems running Stalwart Mail Server, you found a bug or just have a question,
do not hesitate to reach us on [Github Discussions](https://github.com/stalwartlabs/mail-server/discussions),
[Reddit](https://www.reddit.com/r/stalwartlabs), [Discord](https://discord.gg/aVQr3jF8jd) or [Matrix](https://matrix.to/#/#stalwart:matrix.org).
Additionally you may become a sponsor to obtain priority support from Stalwart Labs Ltd.

## Roadmap

- [x] Performance enhancements
- [x] Distributed SMTP queues
- [x] Web-based admin panel
- [ ] JMAP Calendar, Contacts and Tasks support
- [ ] CalDAV and CardDAV support

See the [open issues](https://github.com/stalwartlabs/mail-server/issues) for a full list of proposed features (and known issues).

## Funding

Part of the development of this project was funded through the [NGI0 Entrust Fund](https://nlnet.nl/entrust), a fund established by [NLnet](https://nlnet.nl/) with financial support from the European Commission's [Next Generation Internet](https://ngi.eu/) programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 101069594.

If you find the project useful you can help by [becoming a sponsor](https://liberapay.com/stalwartlabs). Thank you!

## License

Licensed under the terms of the [GNU Affero General Public License](https://www.gnu.org/licenses/agpl-3.0.en.html) as published by
the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
See [LICENSE](LICENSE) for more details.

You can be released from the requirements of the AGPLv3 license by purchasing
a commercial license. Please contact licensing@stalw.art for more details.
  
## Copyright

Copyright (C) 2024, Stalwart Labs Ltd.