How to block "on behalf of" addresses?

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How to block "on behalf of" addresses? - Monday, April 30, 2018 3:18 PM
Hi All,
I have a repetitive spammer from China that sends the same email to me constantly (Multiple times per day). The subject and message body change frequently. I've been using keyword blocking but I still receive several (maybe 20%) because of variations in the wording. I'd like to block the email address but it's one of  "sent on behalf of" emails. Here is the specific:
From: Maggie <> on behalf of Maggie <>
The "" portion is always the same and the other address is different every email. How do I block this using the Email Blocklist Module? Do I select "Sender"? MIME Sender? or SMTP Sender? Will that even work?
Thank you,

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Re:How to block "on behalf of" addresses? - Friday, July 06, 2018 10:18 AM
"Sent on behalf of" is how Outlook renders a MIME FROM header when it's different from the SMTP user. You should be able to block this using MIME Sender.
I'd just block by 'Sender' which AFAIK blocks either. If you test it and this doesn't work though, block by MIME sender.
The other option is to use Advanced Content Filtering, and create a regex for the exact header of the email. That gives you an option to treat such emails differently from your blocklist.