In order to be able to use the Secure Mail Gateway, the following setup steps are necessary on the customer side (mail server or application of the customer).


The following DNS A Record must be stored as SMARTHOST in the mail server or application:

For the connection of systems from the Open Telekom Cloud to the SMARTHOST the Port 25 is available. (Other ports are not active on the secure mail gateway for mail acceptance.)


Authentication with username is now necessary to reduce the suspicioin of spam and increase security through TLS authentication. Username will be provided by Cloud Handling Support (contact:

Customer costs: ~23€/month. Will be invoiced via OTC.

T-Systems eMail Protect Pro (in case of incoming mail requirement)

This is a direct and full managed service from T-Systems (not an OTC service!) available at:

Contact: Available contacts: FMB Secure-E-Mail <>
Customer costs: to be requested at Secure Mail team. Will not be invoiced by OTC.