A gateway without a list of valid addresses accepts mail for any address. Which Active Directory objects carry deliverable addresses, what Exchange recipient filtering does and how to set up…
Outlook supports S/MIME out of the box, but not OpenPGP. The options that still exist, what Microsoft itself says about PGP in Microsoft 365, and why companies prefer to handle PGP at the gateway…
Microsoft Entra Connect syncs local Active Directory with the Microsoft cloud. What it is needed for, which rights the sync demands and when email security works without it.
