Customers with adresses:

Note: SSL has to be activated in the settings for all informations listed below.

Incoming mail server
IMAP4: (Port 993)
POP3: (Port 995)
Outgoing mail server
SMTP: (Port 465)
Note: The SSL settings must be activated for the above specifications.

Customers with their own domain:

User name
Incoming mail server
IMAP4: (Port 993) -> SSL/TLS
POP3: (Port 995) -> SSL/TLS

Outgoing mail server
SMTP: (Port 587) -> STARTTLS