This document describes how to rate limit maximum message size by sender domain.
Many mail administrators would like to prevent certain domains from flooding their networks and using up valuable bandwidth.
This can be accomplished using the Host Access Table (HAT) of an Cisco Email Security Appliance. For example, if the free mail domains, such as Hotmail, Comcast, and Yahoo are sending a large volume of messages, you can create a special Sender Group for these domains and limit their ability to consume bandwidth.
- Via the GUI, navigate to the Mail Policies tab, and choose the Host Access Table -> HAT Overview link in the left menu
- Click "Add Sender Group"
- Give your Sender Group a name, perhaps "FREEMAILLIST" and fill in the rest of the fields
- Click "Submit and add Senders>>"
- Add in the domains you want to throttle
- Navigate back to the "Hat Overview" page and assign your new Sender Group to the appropriate Mail Flow Policy
- If needed, create a specific Throttle Policy for this Sender Group
- Settings that may be of use include
- Maximum message size:
- Maximum rcpts per hour: