A transparent proxy operates by intercepting traffic without client configuration, typically redirecting HTTP (port 80) or HTTPS (port 443) to a proxy port on the firewall. In Palo Alto Networks NGFWs, when configuring a NAT rule for a transparent proxy, the standard translated port is 8080 (Option C), commonly used for proxy services. This port is where the firewall redirects client traffic for processing (e.g., URL filtering or decryption) before forwarding it to the destination.
Option A (80) is the original HTTP port, not a proxy port. Option B (443) is for HTTPS, not transparent proxy redirection. Option D (4443) is non-standard and unrelated. Documentation and best practices confirm
8080 for this use case.
Reference: PAN-OS 11.2 Administrator's Guide, "NAT" section - Transparent Proxy Configuration; Palo Alto Networks Tech Docs - Transparent Proxy Deployment.