How to install IMAP on ClearOS

yum install app-imap

And visit https://example.org:81/app/imap to configure

This installs Cyrus IMAP. You likely also want to: install SMTP

This provides a standard IMAP server. Some operating systems offer a built-in IMAP client. If yours doesn't or you want something more powerful, here are some options:

In the ClearOS admin panel, you can determine which users have access. Adding a new user with IMAP enabled does not automatically create the mailbox. The things that trigger this are:

  • for successful login events,
  • for email messages that arrive for a user
    • Can be done with
      $ mail -s "This is the subject" somebody@example.com <<< 'This is the message'
  • when a Sieve script uses the “fileinto” action.

Optional: How to install Roundcube on ClearOS

See also: ClearOS and Cyrus IMAP 3 testing