Microsoft Exchange

General information about using Exchange

  • Important information!

For security reasons, VPN must be active for using the Exchange Mailsystem outside the RPTU campus network. If you have any questions about this, please contact rz-support(at)rptu.de.

VPN setup


  • The use of Exchange is only available for RPTU employees and is free of charge. A valid RPTU account is required.
  • The mailbox has a quota of 10GB. If the quota exceeds a certain value, Exchange will send an e-mail with the information that the quota is almost used up. If the mailbox continues to fill up, no further e-mails can be sent or received.
  • The mailboxes are backed up several times a day, a restore is possible up to 30 days back. In addition, as a user, you can restore items that you have accidentally deleted yourself; here too, a 30-day period applies.
  • The following mail clients are currently supported:
    • Microsoft Outlook for Windows from version 2016
    • Microsoft Outlook for Mac from version 2013
    • Apple Mail on Mac OS Version 11 (Big Sur)
    • iOS for iPhone and iPad from version 15
    • Access via browser using Outlook Web App at https://email.uni-kl.de
    • No general support can be guaranteed for Android. For security reasons it is recommended to use at     least version 4.x.
  • The maximum size of attachments is 50 MB. If the attachment is an archive (such as ZIP or RAR), it is possible that less can be sent due to technical reasons.
  • It is recommended to limit the maximum number of recipients in an e-mail to 100. Some e-mail providers do not accept e-mails with a large number of recipients. For large distribution lists or for distribution lists with external mail recipients, we recommend using RPTU's Sympa List server.
  • When an employee leaves the RPTU, the RPTU account goes through an automated deletion process. On the day the RPTU account is deleted, the Exchange mailbox is also irrevocably deleted. Therefore, make sure to back up any data you still need. Please observe the regulations on data protection and consult your supervisor if you have any questions.
  • Functional accounts are recommended for group calendars or contact lists. For this purpose, an RPTU account has to be applied for, just like for an employee, whereby "Functional Account for Exchange" has to be added manually on the application form.
  • The Microsoft Outlook app for iOS/Android has been purchased by Microsoft and cannot be used at RPTU. The problem is, that this app stores the login data and all mailbox contents on servers in the USA in plain text. Therefore a filter has been set up so that this Microsoft Outlook app for iOS/Android cannot connect to our Exchange E-Mmail Server.

Migration of a mailbox to Exchange

The migration of existing mailboxes including the transfer of existing data to a new Exchange mailbox (mails, contacts, calendar) is usually carried out by RPTU free of charge. The migration can be carried out by a local IT administrator or with the support of RPTU. Should a migration be particularly complex and/or time-consuming, or should many mailboxes be migrated in a short period of time, costs will be incurred within the scope of a rent-to- trainee support. If the mailbox is located in Outlook or Thunderbird, the migration can usually be carried out easily. Other mail clients may require more effort, which may result in costs.

If you want to use Exchange directly after applying for a new RPTU account, you have to perform a migration at the moment, since the Exchange mailbox cannot be created automatically with an RPTU account due to technical reasons. It is also recommended to migrate the RPTU mail address automatically generated when creating the RPTU account to Exchange as well, so that you only have to set up and maintain one mail account. Questions and requests for setting up an Exchange account should be directed to hotline(at)rhrk.uni-kl.de.

There is only one mail address in Exchange that can be used for sending, but additional aliases can be set up for receiving. (Example: mustermann@verw.uni-kl.de is the primary address for sending and receiving, while mustermann@rhrk.uni-kl.de can be used as another address for receiving only).

Outlook Web App (Webmail)
Outlook Web App Exchange Terminplanung
Outlook Web App Out of Office Assistant
Outlook Web App
Outlook 2016 without domain
Outlook 2016 Out of Office Assistant
Exchange configuration for Android smartphones (version 5.0 Lollipop)
Exchange configuration with Mac OS
Exchange configuration for iOS