sendmail X is a modularized message transfer system consisting of five (or more) persistent processes, four of which are multi-threaded. A central queue manager controls SMTP servers and SMTP clients to receive and send email messages, an address resolver provides lookups in various maps (including DNS) for mail routing, and a main control program starts the others processes and watches over their execution. The queue manager organizes the flow of messages through the system and provides measures to avoid overloading the local or remote systems by implementing a central control instance. sendmail X is simple to configure using a syntax that is easy to understand and use. It is intended to be used as a secure and efficient mail gateway. It does not provide any mail content modification capabilities such as address masquerading.
mysqmail is a replacement for the qmail standard checkpasswd that performs authentication with a MySQL table. After authentication, it sets up two environment variables that it uses to perform traffic accounting. For SMTP, it provides an alternative logger for the qmail-send program. Instead of logs, it writes the traffic to a MySQL table for the related domain.
Rumble is a mail server suite for SMTP (ESMTPSA), HTTP, POP3, and IMAP4v1 with an extensive C/C++ and Lua API for scripting. It comes with support for SSL/TLS, SQLite, and MySQL and has a Web-based administration and Web mail feature. Additional included modules feature greylisting, DNS blacklisting, SpamAssassin support, and dynamic performance scaling as well as a multithreaded structure that allows for clustering of multiple servers for one or all domains. With the Lua API you can create your own new server mailing lists, CRM software, e-marketing, and other extensions within minutes.
Sendmail Extended Queue Groups is an m4 file that can be used to add extended queue groups to Sendmail 8.12.x. Extended queue groups allow administrators to choose multipe queue groups based on the sender, recipient, or sender and recipient pair. This improves upon the default plain queue groups feature, which can only operate on recipients.
The Gordano Messaging Suite (GMS) is a highly flexible and reliable suite of messaging products. Customers can choose which components meet their needs from email, Webmail, collaboration, instant messaging, calendaring, SMS, and list server software all of which can be complimented by high level anti-spam, anti-virus, and archiving options.
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.