Exchange Online transport (mail flow) rules are a powerful way to manipulate messages as they pass through the transport system. In this example, we look at how to BCC messages sent by some employees for management review. I’m not sure that this is a good idea (for many reasons), but the need does exist to copy messages automatically, so we explore the use of transport rules as a solution.
Exchange Online transport rules can block outbound email stamped with selected Office 365 Sensitivity Labels to make sure that confidential material doesn’t leave organizations. The transport rule is very easy to construct with the only complication being the need to discover the GUID of the sensitivity label you want to block. Fortunately, PowerShell gives us an easy way to find a label’s GUID.
Helping Exchange Protect Users from Bad Email Given the amount of spam floating around today, it comes as no surprise that many organizations deploy an Exchange transport rule to mark inbound external email with a suitable warning. This is a straightforward rule to configure and it can help stop users being fooled by bad messages …
Office 365 tenants can use Exchange transport rules to apply autosignatures to outbound email, including messages protected with encryption. You can even include some properties of the sender extracted from Azure Active Directory, and you can add an exception so that the autosignature isn’t applied to replies.
Office 365 offers different ways to apply encryption to important messages. When those messages hold sensitive data known to Office 365, like credit cards or passport numbers, we can define a transport rule or DLP policy to protect outbound email automatically. And while you can define rules and policies through the GUI, PowerShell is available too.