Buni Meldware Communication Suite is an enterprise groupware product providing an email server, calendar server, and a Web mail client. The Web mail portion is written using Adobe's Flash and provides a rich cross-browser experience. Protocol support includes IMAP, POP, SMTP, iCAL, WCAP, and more. It uniquely supports full database email storage as well as file system storage of emails on major database platforms, and is easily installed via a Web Start graphical installation process.
DJIGZO Email Encryption Gateway is a centrally managed email server that encrypts and decrypts incoming and outgoing email at the gateway level. Djigzo currently supports two encryption standards: S/MIME and PDF encryption. The built-in Data Leak Prevention (DLP) module can be used to prevent certain information from leaving the organization via email. DLP can be configured to filter on credit card numbers, bank account numbers, excessive amounts of email addresses or other personal information in one email message, and more. DJIGZO can be installed on most Linux and Unix based systems. Installation packages are available for Ubuntu, Debian, Red Hat and CentOS. A ready to run virtual appliance for VMware and Hyper-V is available. An add-on for BlackBerry is available.
GreenMail is a suite of email servers for testing purposes and sandbox development. It supports SMTP, POP3, and IMAP (including SSL) and can be embedded into any Java application or unit test. The GreenMail Service (SAR) extension runs as a JBoss embedded developer mail server sandbox, manageable via JMX.
JSpamfilter is software that intercepts connections from remote Internet mail servers before they can connect to your mail server. The originating IP address for the inbound connection is then checked against one of the DNS-based SPAM Blackhole (DNSBL) lists maintained on the Internet by various organizations. If the check passes, the connection is allowed to proceed to your mail server; if it fails, the connection is told that the mail server is unavailable, then dropped.
Java SMTP Mail Component provides an easy API to send email from an application. The API has option to send emails directly to the recipients mail server without a relaying mail server. Plain authentication is supported for mail server authentication. Mail attachments are supported using MIME.
Jsmtpd is a small and modular SMTP server daemon. It is heavily based on plugins, and currently supports spam detection (Spamassassin, Jasen, RBL servers, and BlackList), anti-virus (Clam Antivirus), Recipient rewriting, and many other filters. Filtering is done with a customisable tree of filters. Almost all functionality is implemented as plugins, making it easy to fit your needs.