MailSite SE - Version 6.0.6 Rockliffe MailSite SE is easy-to-use and standards-based email server software for small enterprises. Rockliffe MailSite SE is an award-winning Windows-based SMTP, POP3 and IMAP4 email server that also includes advanced protection against viruses and spam, powerful content filtering, multi-language web messaging, and a wireless email client. Rockliffe MailSite SE offers a cost effective email alternative to Microsoft Exchange.