What are two prerequisites for implementing undesirable URL protection in Cisco ESA?

Undesirable URL protection is a feature that allows Cisco ESA to detect and block messages that contain URLs that lead to malicious or unwanted websites, such as phishing, malware, or adult content sites. To enable this feature, outbreak filters and antispam scanning must be enabled on Cisco ESA.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 6-17.