Forum Discussion
Block outbound RMS Encrypted Emails with Exchange Transport Rule?
Is there a way to prevent RMS/IRM protected emails from being sent externally?
We unsuccessfully tried using an Exchange Transport rule to block emails sent externally when the MessageType = Encrypted (the emails still are sent out).
The goal is to use RMS/IRM for internal emails only, but the business wants to insure that users do not attempt to send emails protected by RMS/IRM externally.
Thanks!
Circling back on this - we worked with MSFT Support and they confirmed it no longer works using rpmsg.message.
They work-around they provided, which we confirmed works, is checking for a message type that is "Permission Controlled"
Funny, customers usually care about the opposite scenario :)
I believe the "encrypted" option for message type refers to S/MIME, for RMS/AIP protected messages try creating a rule that looks the following header - Content-Class: rpmsg.message
Or the "msip_labels" header, but that's only added when manually labeling the email I suppose.
It does not seem to be blocking it. Does this rule look right to you? If so, shouldn't the rule take effect in ~15 minutes? It has been 45 minutes.
You probably have to "sanitize" it, as the . symbol has special meaning when using regex ("matches"). Or just try the "header includes words" condition.
