Cryoserver - Cryoserver is an all-in-one email archiving solution that empowers you to preserve your email in a tamper-evident archive, making you transform your data into a useful archive for everyday use.
dmarcian - Safeguard your email from abuse
Gmvault - Backup the emails in your Gmail account.
Mimecast Gateway - Mimecast Gateway is a SaaS-based email security solution that uses sophisticated, multi-layered detection engines and intelligence to protect email data and employees from malware, spam, advanced threats and zero-day attacks.
imapsync - Console-based utility for migrating IMAP mailboxes.
Hornetsecurity - Hornetsecurity offers you comprehensive, integrated managed e-mail security services.