Dynamic Block Sender List

Question

Hello,

The company I work for utilizes a couple different threat feeds. These threat feeds supply us with a list of domains that we should be blocking email from. We are trying to incorporate this into Office 365 so we can have these domains blocked immediately. These lists would tend to be dynamic and change from time to time. I've searched around a lot and have found ways to block single domains at a time via Powershell but this would not be feasible. Is there a way to use a dynamic list to feed into Office 365 to block emails from reaching our users?

Answer 1

Hello EL-THarding,

Have a good day. Thanks for your post in forum.

Regarding your description, as per my knowledge we cannot dynamic list feed into Office 365 for block sender. It is not feasible. We can only manually add an email address and domain name in spam filter block list under Protection in Office 365 Admin Center. The other option, we can make transport rule for block domain and we can block senders for a single user and in bulk in Office 365.

On the other hand, regarding dynamic Block Sender list, it cannot meet your requirement. Therefore we recommend you that please give a feedback via our Uservoice service https://office365.uservoice.com/forums/273493-office-365-admin. Many features are built based on customer’s feedback. Microsoft will always focus on customer’s feedback and experience, some new features would be added to the services based on your feedback in the future, and your good ideas will be very helpful for them to improve the service.

However, you can do following workarounds method for block domain list.

1. Block domain from Office 365 Exchange Admin Center. Following are the steps.

·         Login Office 365 portal.

·         Go to Admin Center.

·         Click on Exchange option.

·         Go to Protection.

·         Click on Spamfilter.

·         Double click the default rule or create a new one.

·         Go to Block List.

·         Here you can block senders and/or domains.

2. For block domain, you can make transport rule. Following are the steps.

·         Login Office 365 portal.

·         Go to Admin Center.

·         Click on Exchange option.

·         Click on Mail flow option.

·         Under Rule tab create following screenshot rule and Save it.

3. For block senders in Office 365 via PowerShell cmndlet, you can refer this detailed article https://docs.microsoft.com/en-us/exchange/troubleshoot/spam-and-malware/set-up-safe-blocked-senders

I am appreciating your cooperation and time.

Regards,

Darpan

Answer 2

Doing an internet search would turn up many examples of using data from a text file.

Answer 3

I don't have a ton of powershell experience but I'm assuming I would set a variable to call the text file and then when i use powershell to update the block domain list, i would call the variable?

Answer 4

Typically with Powershell you can use data in a text file to feed a PowerShell command which then can go through all the items in the text file and process them by adding them to the block domain list in O365.