You can also apply custom email and IM spam policies. You must first create these policies to make them available from the selection menus.
To select spam or spim policies for a policy group
Symantec Brightmail Gateway provides a default policy: Failed Bounce Attack Validation: Reject message. You can also edit this policy or create a new policy, which must contain the condition, If a message fails bounce attack validation and actions to be taken should bounce address tag validation fail.