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Tata1980's avatar
Tata1980
Copper Contributor
Jul 19, 2019

Hello Guys. How do i block malicious senders in office 365 security and compliance?

We have office 365 as our email security gateway. How do i block malicious senders in office 365 security and compliance?

4 Replies

  • ankit shukla's avatar
    ankit shukla
    Iron Contributor

    Tata1980  You can configure list of Block Senders or even Block the entire sender domain itself.

     

    https://docs.microsoft.com/en-us/office365/securitycompliance/create-block-sender-lists-in-office-365 

     

    IP may keep changing for spammers so it is not recommended to block a specific ip because once ip is changed, it will be able to bypass your connection filter and ultimately be blocked on Spam Filter again.

     

    Additionally when a small group of people are impacted on our Organization (an email may be irrelevant for HR team flagged as Marketing but may not be spam for your Sales team), that is when you should use or encourage your users to use Outlook Blocked senders.

     

    To review who are all already added in Blocked sender's list , use PowerShell - Get-BlockedSenderAddress

     

    Cheers !

    Ankit Shukla

     

     

     

     

    • altria92's avatar
      altria92
      Copper Contributor

      ankit shukla 

      How can I use import-csv with get-blockedsenderaddress to see which users are blocked based on a list of email addresses?

      Also, once the list is checked, can I add a block for those that may not have one on the lists

      Finally i would like to use the same/modified list for remove-blocked sender address.

      Thanks,
      A

  • Rnishat0786's avatar
    Rnishat0786
    Iron Contributor

    Tata1980 

     

    You can block the Ip or IP range using connection filter … refer below article

     

    https://docs.microsoft.com/en-us/office365/securitycompliance/configure-the-connection-filter-policy

     

    To block the domain or sender.. use Anti Spam policy or create a transport rule.. refer below article..

     

    https://docs.microsoft.com/en-us/office365/securitycompliance/create-block-sender-lists-in-office-365

     

    Thanks

     

    Robin Nishad

    Sr Consultant

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