Configure S/MIME to use a secure mail gateway

[lucastoehr]

For security reasons i wanted to activate the S/MIME protocol in our instances. 

I followed the ServiceNow documentation for setting up S/MIME for mails and i could successfully do the neccessary configurations.

Nevertheless i'm currently stuck because the provided documentation only handles the case, that a instance directly communicates with the client of the recipient. However, in our company we have a mail gateway system (Totemomail Software) which is responsible for S/MIME de- and encryptions. The system has access to all the client mail certificates and our mail traffic already goes throught the gateway.

If i understood it correctly, it would be neccessary to upload a mail certificate into our Instances for EVERY user which wants to use mail functionalities. Because of a really high user count and especially because we have a central gateway system which function it is to provide and valdiate the certificates, i would rather configure our Instance to use the certificate of the gateway instead of the certificates of each user.

My (failed) try was, that instead of uploading the recepient's certificates, i uploaded the certificate of our gateway system. Still when i try to de- or encrypt a mail, i get the message that the recipients certificate could not be found. 

Is it somehow possible so use one authority certificate for all de- and encryptions?

[2mustang]

Did you ever figure out how to get this to work? A mail gateway system would make more sense than individual emails