Forum Discussion
MIME in Office ATP
- May 25, 2020
It does check based on content, not just on file extension as detailed for example here: https://docs.microsoft.com/en-us/exchange/security-and-compliance/mail-flow-rules/inspect-message-attachments#supported-file-types-for-mail-flow-rule-content-inspection
Or check the description of the common attachment types filter feature.
You cannot add custom mime types if that's what you're after, but you can add custom extensions.
It does check based on content, not just on file extension as detailed for example here: https://docs.microsoft.com/en-us/exchange/security-and-compliance/mail-flow-rules/inspect-message-attachments#supported-file-types-for-mail-flow-rule-content-inspection
Or check the description of the common attachment types filter feature.
You cannot add custom mime types if that's what you're after, but you can add custom extensions.