This is a carrier-grade Internet mail server with multi-platform support. The software features an array of built-in services, including standards-based SMTP, POP, IMAP and Web mail. It also contains an integrated LDAP directory, a Web server, calendars, scheduling options and a list server. The included SIP Server allows users to communicatein real-time via VoIP, video, instant messaging, anddesktop/application/whiteboard sharing using a variety of SIP compatible third-party devices and utilities. The open interface allows integration with billing, provisioning, and security applications. It also acts as acentral IMAP message store for a variety of integrated messaging applications including fax, voice and SMS/MMS.The program provides anti-spam functions, options for third party anti-spam and anti-virus plug-ins, Web administration, multiple-domain support, dial-up support, IMAP multi-mailbox features, IMAP4rev1, ESMTP,POP3, WebEmail, MailList, LDAP, ACAP, SSL/TLS, CLI, SASL, SNMP and personal Web pages with automated publishing. The optional clustering solution operates as a group of front-end and back-end servers, accessing domain and account data on a shared file server. The architecture enables load balancing and server redundancy.