Enforced TLS
The use of enforced TLS is supported. During the basic configuration of the service, a hybrid encryption protocol is defined at the dispatch domain level to be used for each dispatch. Thus an encrypted dispatch (enforced TLS) is tried with each dispatch by the customer with the given domain. The dispatch is aborted as soon as no encrypted success is accepted on the receiving side.
It is mandatory for Certified Senders Alliance (CSA) IPs to use the enforced TLS for their emails deliveries.