The Cyrus IMAP (Internet Message Access Protocol) server provides access to
personal mail and system-wide bulletin boards through the IMAP protocol.
The Cyrus IMAP server is a scaleable enterprise mail system designed for use
from small to large enterprise environments using standards-based
technologies.
A full Cyrus IMAP implementation allows a seamless mail and bulletin board
environment to be set up across multiple servers. It differs from other
IMAP server implementations in that it is run on "sealed" servers, where
users are not normally permitted to log in. The mailbox database is stored
in parts of the filesystem that are private to the Cyrus IMAP system. All
user access to mail is through software using the IMAP, POP3, or KPOP
protocols.
The private mailbox database design gives the server large advantages in
efficiency, scalability, and administratability. Multiple concurrent
read/write connections to the same mailbox are permitted. The server
supports access control lists on mailboxes and storage quotas on mailbox
hierarchies.
The qmail program is a secure, reliable, efficient simple message
transfer agent. It is meant to be a replacement for the entire
sendmail-binmail system that most UNIX hosts use.
Although qmail holds security and reliability as its top two
priorities, it is also fast. On a Pentium under BSD/OS, qmail can
easily handle 200000 separate messages per day that are injected
and must then be delivered to local mailboxes!
Security and reliability are qmail's two strengths, however. The
qmail package ensures a message, once accepted, will never be lost.
An optional new mailbox format, maildir, even lets users safely
read their mail over NFS, while still accepting new mail deliveries.
The following features are supported: host and user masquerading,
full host hiding, virtual domains, null clients, list-owner rewriting,
relay control, double-bounce recording, arbitrary RFC 822 address
lists, cross-host mailing-list loop detection, per-recipient
checkpointing, downed host backoffs, independent message retry
schedules, a drop-in sendmail replacement, and more!
http://pobox.com/~djb/qmail.html
Postfix attempts to be fast, easy to administer, and secure, while at the same
time being sendmail compatible enough to not upset existing users. Thus, the
outside has a sendmail-ish flavor, but the inside is completely different.
Some feautures:
Connection cache for SMTP, DSN status notifications, IP version 6, Plug-in
support for multiple SASL implementations (Cyrus, Dovecot), TLS encryption and
authentication, Configurable status notification message text, Access control
per client/sender/recipient/etc, Content filter (built-in, external before
queue, external after queue), Berkeley DB database, LDAP database, MySQL
database, PostgreSQL database, Maildir and mailbox format, Virtual domains,
VERP envelope return addresses and others.
Dbmail is the name of a group of programs that enable the possibility of
storing and retrieving mail messages from a database (currently MySQL,
PostgreSQL or SQLite).
* Scalability.
Dbmail is as scalable as the database system that is used for the mail
storage. In theory millions of accounts can be managed using dbmail. One
could, for example, run 4 different servers with the pop3 daemon each
connecting to the same database (cluster) server.
* Manageability.
Dbmail is based upon a database. Dbmail can be managed by changing settings
in the database (f.e. using PHP/Perl/SQL), without needing shell access.
* Speed.
Dbmail uses very efficient, database specific queries for retrieving mail
information. This is much faster then parsing a filesystem.
* Security.
Dbmail has got nothing to do with the filesystem or interaction with other
programs in the Unix environment which need special permissions. Dbmail is
as secure as the database it's based upon.
* Flexibility.
Changes on a Dbmail system (adding of users, changing passwords etc.) are
effective immediately.
Dbmail is the name of a group of programs that enable the possibility of
storing and retrieving mail messages from a database (currently MySQL,
PostgreSQL or SQLite).
* Scalability.
Dbmail is as scalable as the database system that is used for the mail
storage. In theory millions of accounts can be managed using dbmail. One
could, for example, run 4 different servers with the pop3 daemon each
connecting to the same database (cluster) server.
* Manageability.
Dbmail is based upon a database. Dbmail can be managed by changing settings
in the database (f.e. using PHP/Perl/SQL), without needing shell access.
* Speed.
Dbmail uses very efficient, database specific queries for retrieving mail
information. This is much faster then parsing a filesystem.
* Security.
Dbmail has got nothing to do with the filesystem or interaction with other
programs in the Unix environment which need special permissions. Dbmail is
as secure as the database it's based upon.
* Flexibility.
Changes on a Dbmail system (adding of users, changing passwords etc.) are
effective immediately.
Ecartis is a open-source (GNU Licence) software package that adminsters
mailing lists (similar to Majordomo and Listserv). Some of Ecartis's
features include:
- A modular design structure, so that you can compile what you
need (and don't)
- The ability to strip down MIME messages and remove their
attachments.
- Ability to be run in a multi-Virtual Host configuration.
Take a look at the Ecartis website to get a full feature list:
Documentation for the Exim mail transport agent in multiple formats.
The Exim MTA may be installed from any of the ports named mail/exim*
The Exim monitor (eximon) is a graphical user interface for the Exim
mail transfer agent for Unix systems. Eximon is distributed as part
of the standard Exim distribution, but its dependency on XFree86
annoys many administrators.
For this reason, it is available as its own package to allow
administrators to easily install Exim without installing XFree86.
The hashcash tool allows you to create hashcash tokens to attach to
emails you send, and to verify hashcash tokens attached to emails you
receive. A hashcash token constitutes a proof-of-work which takes a
parameterizable amount of work to compute for the sender.
KBiff is a mail notification utility for the KDE project.
Features:
o Pure GUI Configuration
o Session Management
o Panel Docking
o Animated Gifs
o Sounds
o Supported mailbox formats: mbox, maildir, mh, POP3(s), IMAP4(s), and NNTP.