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Michael Donovan's avatar
Michael Donovan
Brass Contributor
Jun 29, 2021

Client-side rules

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It seems incredible that there is no visibility into client-side rules (particularly via PowerShell.)  Our company would like a means of preventing client-side rules that forward emails without using transport rules.  The transport rules simply are not granular enough for this specific issue.  Beyond that, I would think there would be huge security concerns with client-side rules with recent exploits.  

Any thoughts on how to overcome this short coming?

</p>

5 Replies

  • davidbmarker's avatar
    davidbmarker
    Brass Contributor

    Michael Donovanl,

      Good afternoon. I believe you are looking for a PowerShell cmdlet that would let you see Inbox Rules. The following post is more information about the Get-InboxRule cmdlet (https://docs.microsoft.com/en-us/powershell/module/exchange/get-inboxrule?view=exchange-ps)

     

    The two ways that I know how to prevent client-side rules that forward emails:

    1. Control automatic external email forwarding in Microsoft 365 using outbound spam filter policy
      https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/external-email-forwarding?view=o365-worldwide
    2. Transport to stop all auto-forwarding emails - https://docs.microsoft.com/en-us/microsoft-365/business-video/stop-email-auto-forward?view=o365-worldwide
    • Michael Donovan's avatar
      Michael Donovan
      Brass Contributor
      Thanks davidbmarker
      When I run a get-inbox on a mailbox and look at any rules with the value supportedbytask set to false, those always seem to match the client side rules.  I went as far as making a new rule client side and converting another rule to server side.  And I discovered  the change was picked up by my one-line script.

      Get-InboxRule -Mailbox <mailbox> | where {$_.supportedbytask -eq $false} |select Identity, Name

      Do you have any idea what the supportedbytask is?  I feel like I have stumbled onto something, but I would like an expert's opinion.
    • Michael Donovan's avatar
      Michael Donovan
      Brass Contributor

      Thanks for your reply EricStarker 

      When I run a get-inbox on a mailbox and look at any rules with the value supportedbytask set to false, those always seem to match the client side rules.  I went as far as making a new rule client side and converting another rule to server side.  And I discovered  the change was picked up by my one-line script.

      Get-InboxRule -Mailbox <mailbox> | where {$_.supportedbytask -eq $false} |select Identity, Name

       

      Do you have any idea what the supportedbytask is?  I feel like I have stumbled onto something but I would like an experts opinion.

      • EricStarker's avatar
        EricStarker
        Former Employee
        While I appreciate the question, I am a community manager and not a product expert.

        Sorry I can't help you here, but I'm sure you'll get great responses from the experts here!

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