Mailroom

An email server written in pure Rust.

This is very much a work in progress and is nowhere near completion.

What works (not necessarily stable or complete!):

• My implementation of the POP3 protocol
  • Can fool email clients into showing a message in the user's inbox.
    • Tested with Mozilla Thunderbird.
  • Doesn't currently work with TLS or STARTTLS.
  • Very minimal; missing a lot of features
• The configuration file
  • Parsed with serde, then stored in a global static variable
• Logging with Log4rs

What I'm working on:

• A database to store user information and emails
  • Switching to SQLite from Postgres for ease of use.
  • Using sea-orm as the ORM.

What's missing / To do (in order of priority):

• TLS support
  • Automatically get certificates from Let's Encrypt?
• SMTP support
• IMAP support

Things to look into

• DKIM
  • Verifies the authenticity of incoming emails with a hash and digital signature.
  • Mailroom should generate a DKIM signature for outgoing emails and verify the signatures of incoming ones.
  • DKIM public key is stored in the domain's DNS record.
  • https://www.cloudflare.com/learning/dns/dns-records/dns-dkim-record/
  • https://datatracker.ietf.org/doc/html/rfc6376/
• SPF
  • Lists the addresses authorized to send emails on behalf of the domain.
  • Domain list is a DNS record.
  • Mailroom should reject incoming messages that are not from the incoming domain's SPF list.
  • Pretty much mandatory if you want other email services to accept emails from your domain.
  • https://www.cloudflare.com/learning/dns/dns-records/dns-spf-record/
  • https://datatracker.ietf.org/doc/html/rfc7208
• DMARC
  • Instructs other domains how to deal with emails that fail DKIM and SPF.
  • https://www.cloudflare.com/learning/dns/dns-records/dns-dmarc-record/
  • https://datatracker.ietf.org/doc/html/rfc7489

Setup

(optional) Set an environment variable called CONFIG_PATH to the path of config.toml.

Migration

Run DATABASE_URL=sqlite://sqlite.db sea-orm-cli migrate refresh

Generate models

sea-orm-cli generate entity -u sqlite://sqlite.db -o src/database/models

License

Mailroom - A mail server written in Rust

Copyright (C) 2023-2024 Mark Ghebrial

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.