A transparent proxy intercepts traffic from a client to a web server without requiring any configuration on the client's browser. The PAN-OS firewall uses a Policy-Based Forwarding (PBF) rule to identify and redirect the web traffic to its internal proxy engine. The client remains unaware of this interception. The question's description of traffic being "redirected to the proxy" while containing the web server's destination IP address directly aligns with the operational mechanism of a transparent proxy.

A. DNS proxy: This feature intercepts and forwards DNS queries to a specified DNS server. It does not handle HTTP or SSL web traffic redirection.

B. Explicit proxy: This method requires the client browser to be explicitly configured to send all web traffic directly to the firewall's proxy IP address and port.

C. SSL forward proxy: This is a decryption policy type used to decrypt and inspect SSL/TLS traffic. It is not a method for directing traffic to the proxy itself.

1. Palo Alto Networks PAN-OS® Administrator's Guide 11.0 (Nova): In the section on Web Proxy

the guide distinguishes between the two primary methods.

For Transparent Proxy: "In a transparent proxy deployment

you must configure a Policy-Based Forwarding (PBF) rule to redirect web traffic from the client to the firewall. The client is unaware that a proxy is intercepting its web traffic..." This directly supports the use of the term "redirected" for this mode.

For Explicit Proxy: "In an explicit proxy deployment

you must configure the client’s browser to direct web traffic to the firewall." This highlights the requirement for client-side configuration

which differs from the scenario.

Reference Location: PAN-OS® Administrator's Guide 11.0 > Web Proxy > Configure Web Proxy.

2. Palo Alto Networks PAN-OS® Administrator's Guide 11.0 (Nova): The guide for Policy-Based Forwarding confirms its role in redirection.

For PBF: "Policy-Based Forwarding (PBF) allows you to create forwarding policies that redirect traffic based on specific parameters..." This reinforces that PBF is the mechanism for redirection in a transparent proxy setup.

Reference Location: PAN-OS® Administrator's Guide 11.0 > Network > Policy-Based Forwarding.