The Allowed and Blocked Senders list lets you create lists of allowed and blocked email addresses and domains. The Allowed and Blocked Senders feature is only applicable to domains with anti-spam and anti-virus scanning enabled. Incoming messages are evaluated against user allowlists and denylists after AS/AV scans are completed. If the Header from field of that message matches against a domain in your blocked senders list, the message is blocked and quarantined. Blocked messages are quarantined with the Policy Action - Fail verdict. If the Header from field of a message matches a domain in your allowed senders list, the message is delivered. MTAs ignore the antispam verdict of allowed messages, but antivirus and advanced threat scan verdicts still apply to the message.
If a custom or connect rule created by an administrator matches the same email as your allowed senders list, the admin-defined rules supersede your allowed senders list.
If one or more email recipients have listed the sender domain on the allowed list or blocked list, message splitting occurs. For example, if User 1 lists a domain on their allowed senders list and User 2 lists the same domain on their blocked senders list, the message is split into different messages with unique message IDs. Each message is scanned differently based on each recipient's allowed and blocked senders lists. The original message appears in Email Trace with the status "Split", followed by the split versions of the original message with their respective message IDs and verdicts. Email Trace is only visible to Email Security — Cloud administrators.
Note
See Accessing the end user interface for information on how to access the Allowed and Blocked Senders page.
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Senders you allow and block appear in the same list in the Allowed and Blocked Senders page. You can search for an email address or filter for it based on whether it is a blocked or allowed address.
To search for a sender:
In the search bar, enter at least the first three characters in a sender address or domain. Special characters are not allowed.
Press Enter.
To filter for a list of allowed or blocked senders only:
Click Show All next to the search bar.
Select Allowed or Blocked from the drop-down menu. The list updates itself.