I Have More than One E-Mail Address - Does this Mean that I Have More than One Mailbox?

Users can have two or more e-mail addresses simultaneously, e.g. joe.bloggs@tum.de and j.bloggs@tum.de. This means that there is only one mailbox, reachable under different e-mail addresses. Also your e-mail-quota (storage size) remains the same.

You can set those e-mail addresses in TUMonline.