My company is looking for an internal email (messaging) system to replace our current system. We are using an email server with a RoundCube front-end that only sends encrypted emails to itself. Emails never leave the server, and all the accounts are protected by user names and passwords, obviously.
We cannot move to a system like Jabber, Slack, or any other IM-based system since a lot of our users would consider something like that as having a steep learning curve.
Using email is not necessary, so we can use a database-based system. We'll be starting from fresh, so migration is not needed. We do not need anything more than a system that sends and receives emails/messages, and an admin panel to manage users.
Summary of needs:
- Accounts secured by username/password
- Messages do not leave system
- System must be hostable on a web server
- Email- or database-based system
- Messages should be file-attachable