The filter-rspamd OpenSMTPd filter implements the Rspamd protocol and allows OpenSMTPd to request an Rspamd analysis of an SMTP transaction before a message is committed to queue.

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.

Dovecot is a mail server whose major goals are security and reliability. It supports mbox/Maildir and its own dbox/mdbox formats.

nmail is an easily configurable terminal-based email client with a ncurses user interface similar to alpine and pine.

The sendgmail command provides a minimal sendmail-compatible front-end that connects to Gmail using OAuth2. It is specifically designed for use with git send-email. The command needs a Gmail API key to function.

Guix's version of sendgmail has been patched for compatibility with all known forks, including support for non-@gmail.com email addresses.

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

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

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.

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.

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

Email::MIME::ContentType parses a MIME Content-Type header.

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

The purpose of this mail library is to provide a portable, efficient framework for different kinds of mail access: IMAP, SMTP, POP and NNTP. It provides an API for C language. It's the low-level API used by MailCore and MailCore 2.

Mail::AuthenticationResults parses the message header field that indicates the message authentication status as per RFC7601. This module is not fully compliant with the RFC but it tries to implement most styles of Authentication-Results header seen in the wild.

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

Sieve-connect lets you view, upload, edit, delete, and otherwise manage Sieve scripts on any mail server that speaks the ManageSieve protocol, as specified in RFC 5804.

Sieve (RFC 5228) is a specialised language for e-mail filtering. Sieve scripts are stored on the server and run whenever mail arrives. They can automatically sort new messages into folders, silently reject them, send an automated response, and more.

sieve-connect is designed to be both a tool which can be invoked from scripts as well as a decent interactive client. It supports TLS for connection privacy, as well as authentication with SASL or GSSAPI client certificates. It should be a drop-in replacement for sieveshell from the Cyrus IMAP project.

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

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

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.

Procmail is a mail delivery agent (MDA) featuring support for a variety of mailbox formats such as mbox, mh and maildir. Incoming mail can be sorted into separate files/directories and arbitrary commands can be executed on mail arrival. Procmail is considered stable, but is no longer maintained.

Fetchmail is a full-featured, robust, well-documented remote-mail retrieval and forwarding utility intended to be used over on-demand TCP/IP links (such as SLIP or PPP connections). It supports every remote-mail protocol now in use on the Internet: POP2, POP3, RPOP, APOP, KPOP, all flavors of IMAP, ETRN, and ODMR. It can even support IPv6 and IPSEC.

Fetchmail retrieves mail from remote mail servers and forwards it via SMTP, so it can then be read by normal mail user agents such as mutt, elm or BSD Mail. It allows all your system MTA's filtering, forwarding, and aliasing facilities to work just as they would on normal mail.

OfflineImap synchronizes emails between two repositories, so that you can read the same mailbox from multiple computers. It supports IMAP as REMOTE repository and Maildir/IMAP as LOCAL repository.

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