Defanging is the process of modifying a URL in a message to prevent it from being clickable. This can help protect users from malicious links that have a low URL reputation score. Defanging is one of the actions that can be configured in the Incoming Content Filter on the Cisco ESA. The other actions are Quarantine, FilterAction, and ScreenAction. Quarantine sends the message to a quarantine area for further inspection. FilterAction applies a predefined action such as drop, bounce, or deliver. ScreenAction displays a warning message to the user before allowing them to access the URL. Defanging is the only action that disables the links in the message without affecting the delivery or visibility of the message12. References: 1: URL Filtering on the Cisco IronPort ESA - Mikail's Blog 2: Configure URL Filtering for Secure Email Gateway and Cloud Gateway - Cisco Reference: https://www.cisco.com/c/dam/en/us/products/collateral/security/esa-content-filters.pdf