Is there a way to always enforce SPX encryption based on the "from" email address?
Looking for a solution that will not require the user to add a custom header or type a particular word or phrase.
I've not tried but:
individual smtp profile > Data protection > action send with SPX encryption > custom expression eg @remotedomain.com
If that works, you can then just keep adding @whateverdomainyouwant.com in that profile
Just give it a shot. I think it only works for expressions in the body rather than in the sender...