fdm fetches and delivers mail in various ways.

Mail may be fetched from IMAP or POP3 servers, from local maildirs, or read from standard input. It is then filtered based on regular expressions, its size or age, or the output of a (shell) command. It can be rewritten by an external process, dropped, left on the server or delivered into maildirs, mboxes, to a file or pipe, or any combination.

fdm is primarily designed for use by a single user, but can use privilege separation to safely deliver mail in multi-user setups.

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

This package provides a TNEF stream reader library and related tools to process winmail.dat files.

Balsa is a highly configurable and robust mail client for the GNOME desktop. It supports both POP3 and IMAP servers as well as the mbox, maildir and mh local mailbox formats. Balsa also supports SMTP and/or the use of a local MTA such as Sendmail.

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

This package provides tools for the conversion of Outlook Express data files to standard mailbox format.

Pigeonhole adds support for the Sieve language (RFC 5228) and the ManageSieve protocol (RFC 5804) to the Dovecot e-mail server.

Sieve is a language for filtering incoming mail. Messages can be forwarded or sorted into separate folders. Unwanted messages can be rejected or discarded, and, when the user is not available, the Sieve interpreter can send an automated reply.

Sieve is meant to be simple, extensible, and system-independent. The intention is to make it impossible to write anything more complex (and dangerous) than simple mail filters. Unlike most other mail filtering script languages, Sieve does not allow users to execute arbitrary programmes.

Through the ManageSieve protocol, users can remotely manage their Sieve scripts without needing file system access. The server accepts only valid scripts to prevent embarrassing errors later on.

Email::Sender replaces the old and sometimes problematic Email::Send library.

A flexible, extensible mail retrieval system with support for POP3, IMAP4, SSL variants of both, maildirs, mboxrd files, external MDAs, arbitrary message filtering, single-user and domain-mailboxes, and many other useful features. This is a fork derived from getmail 5.14, aimed at Python 3 compatibility.

This package provides extra tables, filters, and various other addons for OpenSMTPD to extend its functionality.

Email::Address::XS implements RFC 5322 parser and formatter of email addresses and groups. Unlike Email::Address, this module does not use regular expressions for parsing but instead is implemented in XS and uses shared code from Dovecot IMAP server.

The hyperkitty Django app provides a web user interface to access GNU Mailman3 archives, and manage it. This interface uses django, and requires some configuration.

This Python module can be used to generate and parse RFC 5451/7001/7601 Authentication-Results email headers. It supports extensions such as:

• RFC 5617 DKIM/ADSP

• RFC 6008 DKIM signature identification (header.b)

• RFC 6212 VBR

• RFC 6577 SPF

• RFC 7281 Authentication-Results registration for S/MIME

• RFC 7293 The Require-Recipient-Valid-Since header field

• RFC 7489 DMARC

• ARC (draft-ietf-dmarc-arc-protocol-08)

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.

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.

This module wraps MIME::Base64 and MIME::QuotedPrint.

Email::Address implements a regex-based RFC 2822 parser that locates email addresses in strings and returns a list of Email::Address objects found. It is recommended to use Email::Address::XS instead.

Notmuch is a command-line based program for indexing, searching, read- ing, and tagging large collections of email messages.

Muchsync brings Notmuch to all of your computers by synchronizing your mail messages and Notmuch tags across machines. The protocol is heavily pipelined to work efficiently over high-latency networks such as mobile broadband. Muchsync supports arbitrary pairwise synchronization among replicas. A version-vector-based algorithm allows it to exchange only the minimum information necessary to bring replicas up to date regardless of which pairs have previously synchronized.

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

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

pan is a Usenet newsreader that's good at both text and binaries. It supports offline reading, scoring and killfiles, yEnc, NZB, PGP handling, multiple servers, and secure connections.

Khard is an address book for the console. It creates, reads, modifies and removes CardDAV address book entries at your local machine. For synchronizing with a remote address book, vdirsyncer is recommended. Khard can also be used from within the email client mutt.

This package implements a functionality to translate standard protocols (SMTP, IMAP, CardDAV) into ProtonMail API requests.