Self-hostable software: Communication - Email - Mail Delivery Agents

IMAP and POP3 server written primarily with security in mind.

POP/IMAP/SMTP/Caldav/Carddav/LDAP exchange gateway allowing users to use any mail/calendar client with an Exchange server, even from the internet or behind a firewall through Outlook Web Access.

JMAP and IMAP server designed to be secure, fast, robust and scalable.

Email (IMAP/POP3), contacts and calendar server.

Feature-rich email archiving solution.