Under certain circumstances, you might want to prevent InterScan™ Messaging Security Appliance (IMSA) from scanning certain types of email messages that could be part of a DoS attack. For example, messages with extremely large attachments would require significant IMSA server resources to scan fully. Additionally, messages addressed to hundreds of recipients are most likely spam or some type of attack.
Rather than consuming IMSA resources to scan these types of email messages, set scan exceptions to bypass scanning and instruct IMSA to take action on the messages immediately.
To configure scan exceptions:
Choose Policy > Scanning Exceptions from the menu.
To set scan exception conditions for email messages based on several conditions, click the Security settings violations link under Exception. The Security Settings Violations screen appears, where you can configure the settings.
To set an action for an exception type, click the corresponding link under Action.
For information on configuring the actions, see the following topics: