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.
Heirloom mailx (formerly known as "nail") is derived from Berkeley Mail and provides the functionality of the System V and POSIX mailx commands. Additional features include support for MIME, IMAP (including caching and disconnected use), POP3, SMTP, S/MIME, international character sets, maildir folders, message threading, powerful search methods, scoring, and a Bayesian junk mail filter. Mailx can be used as a mail batch language in nearly the same way as it is used interactively. It can thus act as a mailbox filter, can fetch mail from remote accounts, and can send files as attachments.
Hep Message Server is software that transfers messages between different messaging systems. Eventually, it should transparently route messages between email, weblogs, and instant messaging. Currently Hep does one thing: fetches news feeds from Web sites and lets you view them in your email client.
Hotwayd is a POP3/SMTP to HTTPMail (WebDAV) gateway. HTTPMail is a somewhat undocumented WebDAV-based protocol used by a variety of mail servers including Hotmail, MSN, Lycos, and Spray. Hotwayd allows you to use any standard POP3/SMTP mail reader to send and receive mail via these servers, similar to the way that Outlook Express can access a hotmail account. It supports features such as folder selection to get folders other than the inbox and proxy server support (if you require a proxy to access the internet).
IP*Works! is a comprehensive suite of more than 40 native Linux class libraries for Internet development. It is a robust framework of enterprise-class tools, enabling rapid integration of any major Internet protocol or technology, including FTP, HTTP, SMTP, POP, IMAP, SNMP, LDAP, DNS, RSS, SMPP(SMS), XMPP (Jabber), SOAP, and WebDav. It includes source code for compilation on various Unix platforms, a framework for Objective-C (Cocoa) Mac OS X development, and native PHP extensions.