Basic features:

• SMTP server (ESMTP supported)
• POP3 server
• TLS/SSL secure connections
• Support of multiple virtual mail domains and accounts
• SMTP authentication (clear-text, secure, POP-before-SMTP)
• Logging
• Account aliasing
• Domain aliasing
• Remote administration
• Cross-platform (Windows, Linux, BSD, etc)

Advanced features:

• Simultaneous multi-user access to a POP3 mailbox
• Finger server
• SMTP protection against spammers (IP-based and e-mail address based)
• Public blacklists: RBL/RSS/ORBS/DUL
• Mailing lists
• Flexible message filters
• Custom mail processing
• SMTP ETRN command support
• Custom POP3/SMTP authentication
• POP3 account synchronizer (fetcher)