Messaging Server provides the following security and access control features:
Support for password login and certificate-based login to POP, IMAP, HTTP, or SMTP
Support for email encryption using S/MIME
Support for standard security protocols: Transport Layer Security (TLS), Secure Sockets Layer (SSL) and Simple Authentication and Security Layer (SASL)
Delegated administration
Client IP address access filters to POP, IMAP, SMTP, and HTTP
Filtering of unsolicited bulk email using system-wide, per-user, and server-side Sieve rules
Support for milter-based email filtering