The SSL Forward Proxy rule type is designed to control and inspect SSL traffic from internal users to external websites. When an internal user attempts to access an HTTPS site, the Palo Alto Networks firewall, acting as an SSL Forward Proxy, intercepts the SSL request. It then establishes an SSL connection with the requested website on behalf of the user. Simultaneously, the firewall establishes a separate SSL connection with the user. This setup allows the firewall to decrypt and inspect the traffic for threats and compliance with security policies before re-encrypting and forwarding the traffic to its destination.

This process is transparent to the end user and ensures that potentially harmful content delivered over encrypted SSL connections can be identified and blocked. SSL Forward Proxy is a critical component of a comprehensive security strategy, allowing organizations to enforce security policies and protect against threats in encrypted traffic.