From the users point of view, our setup is very easy. You don't have to learn many hostnames. You just have to learn the domain name, which is th.physik.uni-frankfurt.de. This is called our virtual service address, and all services are accessed through this domain name.
We provide some mail programs preconfigured for our system. That are Thunderbird, alpine and mutt. If you want to use another program, you have the configure it by your self.
Outgoing mail has to be send to th.physik.uni-frankfurt.de. If you want to send from outside our network (from home etc.) you have to enable TLS (Transport Layer Security) and authenticate with your login name and password. Port for submission is 587.
For incoming mail we provide IMAP support. IMAP works with the mail on the server an does not download it on your computer. The server 'th.physik.uni-frankfurt.de'. You have to use the SSL encryption, regardless if your inside or outside our network.
There also the option to use our webmail front end: https://th.physik.uni-frankfurt.de/webmail/src/login.php
We have now official certificates and you must not get any warning.
For Thunderbird we support autoconfiguration. After entering you mail address and password. Thundbird should automatically detect the correct setting. The final dialog should lock like this: