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Connection Rule examples

This article provides you with the components and settings required to create a specific Connection Rule. For instructions on how to create a rule, refer to Connection Rules.

IP Geo-location connection rule

Since users may have location requirements, we do not provide a default Geolocation Rule. Create this custom rule to detect the location of the connecting IP address and restrict or allow connections from specific areas.

Rejecting large emails

By default, Email Security accepts emails up to 50Mb inbound or outbound. This is done through the Maximum Mail Size default standard rule.


NDR's are not sent from your Mail Server (Domain Route) back to the Internet if your server rejects the message and Email Security routes it. This is due to security policies that help to avoid being blacklisted due to backscatter and NDR spam.

If your mail server (Domain Route) does not accept messages of this size, you can reject the message at the point of SMTP connection. This will make the connecting server create a Non-Delivery Report (NDR) for the sender.


If you create a Message Rule to perform the same function, the sender will not be advised that the email was not received by the recipient.

To change the Maximum Mail Size connection rule follow the steps below:

  1. Go to Products > Email Security > Connection rules.

  2. Double-click the rule's title or click on the Change Rule 75300_3.PNG button.


    The Rule might be called Large Files on your system.

  3. Find the Email Size condition, and click Configure.

  4. Choose a new limit from the Condition Value.

  5. Click the Save emailsecsave.png button.