I’m not sure it has anything to do with kopano. I f"ound" the setting “Mail-Home-Server” in UMC -> User -> advanced settings. NOthing is selectet here but it is possible to selct my kopano-server him self.
it is advisable to do so? What does this setting do?
The management of the user data of the mail server (e.g., e-mail addresses or mailing list) is performed via Univention Management Console and is documented in Chapter 3 User data are stored in LDAP. The authentication is performed using a user’s primary e-mail address, i.e., it must be entered as the user name in mail clients. As soon as a primary e-mail address is assigned to a user in the LDAP directory, a listener module creates an IMAP mailbox on the mail home server. By specifying the mail home server, user e-mail accounts can be distributed over several mail servers, as well (see Chapter 10).