Exim

Exim is a powerful Mail Transfer Agent (MTA). It's the default MTA for Debian / Ubuntu.

Pre-installation
As only one MTA can be installed at the same time on a system, you might be required to unmerge an installed MTA. The package manager will report a block when another MTA is still installed. You can resolve this block by manually unmerging the old mail server. For example you can remove (which might have been installed as the default when a program requested a mail server to be installed) with this command:

Installation
Install :

Configuration
This configuration use spamassasin, clamav, and postgresql, you can adjust to feet your needs, also disallow open relay.

Testing Exim
Once the configuration file is ready we can test the the file with the following command:

If everything goes right we can now start exim

No we must be able to test how exim will route some addresses

Finally we can do the bunny test