Blocked senders

Email Security marks all messages from these senders with a malicious disposition.

How blocked senders work

Blocked senders ensures messages from any sender is automatically marked as malicious, preventing them from reaching users' inbox.

Sometimes, the same email, IP address or domain always sends malicious emails to the company. In this case, you can add an email address, IP address or domain as a blocked sender. You can choose to enter a regular expression by turning Regular expression on.

Configure blocked senders

To configure blocked senders:

1. Log in to Zero Trust ↗.
2. Select Email Security.
3. Select Settings, go to Detection settings > Blocked senders.
4. On the Detection settings page, select Add a sender.
5. Select the Input method: Choose between Manual input, and Upload blocked sender list:
   • Manual input:
     • Sender type:
       • Email addresses: Must be a valid email.
       • IP addresses: Can only be IPv4. IPv6 and CIDR are invalid entries.
       • Domains: Must be a valid domain.
       • Regular expressions: Must be valid Java expressions. Regular expressions are matched with fields related to the sender email address (envelope from, header from, reply-to), the originating IP address, and the server name for the email. For example, you can enter .*@domain\.com to exempt any email address that ends with domain.com.
     • Notes: Provide additional information about the blocked sender policy.
   • Upload blocked sender list: Upload a file no larger than 150 KB. The file cannot can only contain Blocked_Sender, Pattern Type, and Notes fields. The first row must be a header row. Refer to CSV uploads for an example file.
6. Select Save.

CSV uploads

You can upload a file no larger than 150 KB. The file cannot can only contain Blocked_Sender, Pattern Type, and Notes fields. The first row must be a header row.

An example file would look like this:

Blocked Sender, Pattern Type, Notes
john.smith@gmail.com, EMAIL, John Smith
example.com, DOMAIN, Melanie Turner

Export blocked senders

To export all blocked senders:

1. On the Detection settings page, select Sender. Selecting Sender will select all blocked senders.
2. Select Export to CSV.

To export specific blocked senders:

1. On the Detection settings page, select Value(s). Select the blocked senders you want to export.
2. Select Export to CSV.

Edit a blocked sender

To edit a blocked sender:

1. On the Detection settings page, select the blocked sender you want to edit.
2. Select the three dots > Edit.
3. Edit the blocked sender.
4. Select Save.

Delete a blocked sender

To delete a blocked sender:

1. On the Detection settings page, select the blocked sender you want to delete.
2. Select the three dots > Delete.
3. On the pop up message, select Delete.

To delete multiple blocked senders at once:

1. On the Detection settings page, under Blocked senders, select the senders you want to delete.
2. Select Action
3. Select Delete.