DLP rule on Mail Flow not working after June 2022.

Question

Hi,

After July 2022, many client are complaining that the DLP rules are not working. When I have investigated the issue, DLP rules is there and nobody have done any changes.

My concern is Did Microsoft stop support for old DLP mail flow rules? Please let me know.

Answer 1

Hi @Phurba Tshering Gurung

Could you please provide the complete DLP rule you mentioned above?

Here is an official link discussed about Resolve issues that affect DLP policy tips, you could take a reference if that's your scenario.

For DLP in Exchange online, the official document provided below information:

You can easily migrate your legacy Exchange Online DLP policies using the migration wizard. For more information, see Migrate Exchange Online data loss prevention policies to the Microsoft Purview compliance portal.

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Answer 2

@Joyce Shen - MSFT

Thanks for your information and resolution regarding the issue. The issue was very critical and we managed to solved from our own side.

I will just thoroughly explain the issue first. We have two DLP for 2 different purposes. One is DLP and another Mail Flow Rule.

1. When Sensitive information is being shared and received from the organization. The O365 DLP policy will check inside the email Attachment. And we could not achieve another requirement from this rule which is to also track the Sensitive Info being sent in email body and message not in attachment. For that we have created separate Mail Flow rule and which was working fine before.
2. Mail Flow rule to block any email containing any sensitive information being sent from organization in email message.

And the mistake what I did here is, in Mail Flow rule I have merged the existing Mail Flow Rule with my DLP rule . Whenever I merged the Mail Flow rule with my existing DLP rule the Mail flow rule get disabled.

Solution: Removing the merging of DLP in Mail Flow rule did solved the issue.