Cisco Cisco Email Security Appliance C160 Mode D'Emploi

Select the THROTTLED policy from the list.

Check the “Connecting host reverse DNS lookup (PTR) does not match the 
forward DNS lookup (A)” checkbox under Connecting Host DNS Verification.

Submit and commit your changes.

Now, senders for which reverse DNS lookups fail will match the SUSPECTLIST 
sender group and will receive the default action from the THROTTLED mail flow 
policy.

You can also configure host DNS verification via the CLI. See 

 for more information.

First, create a new mail flow policy (for this example, it is named 
THROTTLEMORE) and configure it with more stringent throttling settings:

On the Mail Flow Policies page, click Add Policy

Enter a name for the mail flow policy, and select Accept as the Connection 
Behavior.

Configure the policy to throttle mail.

Submit and commit your changes.