mailprocd is a standalone mail classification and delivery daemon for massive multiuser servers, designed to extend the capabilities of MTAs such as Postfix and sendmail. It embeds perl in C in order to use SpamAssassin efficiently. It implements a process manager with persistent spam checker processes running under users' own UIDs.
JeguePanel is a panel to provide easy management of GNU/Linux servers. It makes services configuration (email and samba) much more easy and efficient, and handles user and permissions management. It's integrated with monitoring tools and a lot of control programs like anti-virus, anti-spam, reports, etc. It has English, Portuguese, and Spanish translations. It can use OpenLDAP, PostgreSQL, or MySQL as a backend, and has full integration with Active Directory. It will show different interfaces to users based on permission levels.
dkimproxy is an SMTP proxy that signs and/or verifies Domain Keys Identified Mail (DKIM). It is designed to work with Postfix. It comprises two separate proxies: an "outbound" proxy for signing outgoing email, and an "inbound" proxy for verifying signatures of incoming email. With Postfix, the proxies can operate as either Before-Queue or After-Queue content filters.
Dkfilter is a DomainKeys implementation for the Postfix mail transfer agent. It is implemented as two filters (or SMTP proxies). There is an "outbound" filter for adding DomainKeys signatures to outgoing email and an "inbound" filter for verifying signatures of incoming email. The filters can be plugged into Postfix as either Before-Queue or After-Queue Postfix content filters. For more information about DomainKeys, see http://antispam.yahoo.com/domainkeys.
Kolab is a groupware system that provides a comprehensive and flexible solution for workgroups. Email, contacts, and group calendars can be managed via the Web, Windows/Outlook, and Linux/KDE. It supports offline synchronization and full seamless support of mixed client environments because the Kolab-XML storage format is fully open and avoids MAPI/TNEF.
odmrd is a server for the "On Demand Mail-Relay" protocol specified in RFC2465. It can be used as a standalone daemon or in inetd mode. It needs a MySQL server to store authentication and optional accounting information. It also requires a BSMTP-capable mailserver, such as Exim or postfix.
libsrs2 is the next generation SRS library. SPF verifies that the Sender address of an email message matches (according to some policy) the client IP address that submitted it. When a message is forwarded, the sender address must be rewritten to comply with SPF policy. The Sender Rewriting Scheme, or SRS, provides a standard for this rewriting that is not vulnerable to attacks by spammers, is easy to parse by common mail filters, and handles multiple hops neatly and safely.