Technology for Resting Email Encrypted Storage (TREES) is a NaCL-based Dovecot encryption plugin. This plugin adds individually encrypted mail storage to the Dovecot IMAP server. It is inspired by Posteo's scrambler which uses OpenSSL and RSA key pairs. TREES works in a similar way, but uses the Sodium crypto library (based on NaCL).

How it works:

1. On IMAP log in, the user's cleartext password is passed to the plugin.

2. The plugin creates an argon2 digest from the password.

3. This password digest is used as a symmetric secret to decrypt a libsodium secretbox.

4. Inside the secretbox is stored a Curve25519 private key.

5. The Curve25519 private key is used to decrypt each individual message, using libsodium sealed boxes.

6. New mail is encrypted as it arrives using the Curve25519 public key.

Email::Simple provides simple parsing of RFC 2822 message format and headers.

This package provides Python bindings to use the Notmuch mail indexing and search library.

Mumi is a Debbugs web interface.

bower is a curses front-end for the Notmuch email system, written in the Mercury language.

Mailman3 allows emails sent to its mailing lists to be archived by any software provided that there is a plugin (loadable by Mailman3) designed to communicate with it properly. This module contains a Mailman3 archiver plugin which sends emails to HyperKitty, the official Mailman3 web archiver.

afew is an initial tagging script for notmuch mail. It provides automatic tagging each time new mail is registered with notmuch. It can add tags based on email headers or Maildir folders and can handle spam and killed threads.

Mairix is a program for indexing and searching email messages stored in Maildir, MH, MMDF or mbox folders.

The mblaze message system is a set of Unix utilities for processing and interacting with mail messages which are stored in maildir folders.

Its design is roughly inspired by MH, the RAND Message Handling System, but it is a complete implementation from scratch.

mblaze is a classic command line MUA and has no features for receiving or transferring messages; you can operate on messages in a local maildir spool, or fetch your messages using fdm(1), getmail(1), offlineimap(1), or similar utilities, and send it using dma(8), msmtp(1), sendmail(8), as provided by OpenSMTPD, Postfix, or similar.

mblaze operates directly on maildir folders and doesn't use its own caches or databases. There is no setup needed for many uses. All utilities have been written with performance in mind. Enumeration of all messages in a maildir is avoided unless necessary, and then optimized to limit syscalls. Parsing message metadata is optimized to limit I/O requests. Initial operations on a large maildir may feel slow, but as soon as they are in the file system cache, everything is blazingly fast. The utilities are written to be memory efficient (i.e. not wasteful), but whole messages are assumed to fit into RAM easily (one at a time).

This package provides a threaded Python IMAP4 client, based on RFC 3501 and original imaplib module.

dovecot-libsodium-plugin provides a libsodium password hashing scheme (such as scrypt) plug-in for Dovecot.

Esmtp is a simple relay-only mail transfer agent built using libESMTP. It sends e-mail via a remote SMTP server using credentials from the user's $HOME/.esmtprc configuration file; see the esmtprc man page for more on configuration. This package also provides minimal compatibility shims for the sendmail, mailq, and newaliases commands.

The mailmanclient library provides official Python bindings for the GNU Mailman 3 REST API.

IMAPFilter is a mail filtering utility. It connects to remote mail servers using IMAP, sends searching queries to the server and processes mailboxes based on the results. It can be used to delete, copy, move, flag, etc. messages residing in mailboxes at the same or different mail servers. The 4rev1 and 4 versions of IMAP are supported.

Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules including regular expressions, statistical analysis and custom services such as URL black lists. Each message is analysed by Rspamd and given a spam score.

Email::MessageID generates recommended message-ids to identify a message uniquely.

GNU Mailutils is a collection of programs for managing, viewing and processing electronic mail. It contains both utilities and server daemons and all operate in a protocol-agnostic way. The underlying libraries are also available, simplifying the addition of mail capabilities to new software. GNU Mailutils provides the following commands:

• dotlock

• decodemail

• frm

• from

• guimb

• mail

• mailutils

• mailutils-config

• messages

• mimeview

• movemail

• popauth

• putmail

• readmsg

• sieve

This package provides a CLI application to execute scripts on IMAP mailbox changes (new/deleted/updated messages) using IDLE and it is mostly compatible with the configuration of imapnotify made with Python.

msmtp is an SMTP client. In the default mode, it transmits a mail to an SMTP server (for example at a free mail provider) which takes care of further delivery.

Alpine is a text-based mail and news client. Alpine includes several tools and applications:

1. alpine, the Alpine mailer

2. pico, the standalone text editor, GNU nano's predecessor

3. pilot, the standalone file system navigator

Urlscan is a small program that is designed to integrate with the Mutt mail reader to allow you to easily launch a Web browser for URLs contained in email messages. It parses an email message or file and scans it for URLs and email addresses. It then displays the URLs and their context within the message, and allows you to choose one or more URLs to send to your Web browser. Alternatively, it send a list of all URLs to standard output. It is a replacement for the urlview program.

Nullmailer is a simple replacement MTA for hosts that receive no local mail and only relay mail to a fixed set of smart relays. It's useful for systems such as Web servers that must be able to send email notifications, without having to run a full-blown MTA such as sendmail or qmail.

Nullmailer is designed to be simple to configure, easy to extend, and secure. It requires little ongoing administration. The included sendmail emulator front-end should allow most (if not all) sendmail-compatible programs to run without any changes.

Mutt is a small but very powerful text-based mail client for Unix operating systems.

The RSS2email program (r2e) fetches RSS/Atom news feeds, converts them into emails, and sends them.