Technical Tip: Configuring and troubleshooting transparent proxy with proxy chaining on FortiGate

[Atul_S]

Description	This article describes the steps to troubleshoot and resolve page timeouts and session timeouts on FortiGate with transparent proxy. The issue is observed when the FortiGate is configured with transparent proxy and the traffic is forwarded to an upstream proxy server.
Scope	FortiGate.
Solution	When configuring a transparent proxy with proxy chaining, traffic matching a firewall policy can be redirected to a transparent proxy policy instead of being forwarded directly to an upstream proxy server. This setup provides greater visibility and control of web traffic. Steps: Enable the 'http-policy-redirect' option on the firewall policy to redirect the matching traffic to the transparent proxy policy on the FortiGate instead of forwarding to the proxy server directly. Create a proxy-policy to allow all the traffic redirected by the firewall policy. Refer to the Technical Tip: Transparent proxy with proxy chaining and Transparent Web Proxy Forwarding for more information. If the issue persists, collect the output of the following commands when the FortiGate is under load:  diagnose wad session list | grep total diagnose wad stats worker execute tac report Analyse the collected output for anomalies, such as uneven worker load or unusually high session counts.