Exchange Admin Center Mail Flow Rules
Navigate to the Exchange Admin Center. Select Rules, + Add a rule
The new rule should have the following key entries:
- Apply this rule if any attachment matches HTML, HTML, html or htm.
- Prepend the subject of the message with [ATTACHMENT-FAIL]
- Apply and prepend a disclaimer
- Generate and Incident report and send it to the domain administrators.
<span style="color:red"><b><p> [ATTACHMENT-FAIL] WARNING, This message has an HTML attachment and may be invalid or contain a virus. USE EXTREME CAUTION in opening any attachment. </p></b></span>
Below is an image of the rule.
Once the rule is created, it will be disabled by default. The rule needs to be enabled to process the rules.