ZyXEL ISG50-ISDN User Guide - Page 332

Chapter 19 HTTP Redirect A client connects to a web proxy server each time he/she wants to access the Internet. The web proxy provides caching service to allow quick access and reduce network usage. The proxy checks its local cache for the requested web resource first. If it is not found, the proxy gets it from the specified server and forwards the response to the client. HTTP Redirect, Firewall and Policy Route With HTTP redirect, the relevant packet flow for HTTP traffic is: 1 Firewall 2 HTTP Redirect 3 Policy Route Even if you set a policy route to the same incoming interface and service as a HTTP redirect rule, the ISG50 checks the HTTP redirect rules first and forwards HTTP traffic to a proxy server if matched. You need to make sure there is no firewall rule(s) blocking the HTTP requests from the client to the proxy server. You also need to manually configure a policy route to forward the HTTP traffic from the proxy server to the Internet. To make the example in Figure 218 on page 331 work, make sure you have the following settings. For HTTP traffic between lan1 and dmz: • a from LAN1 to WAN firewall rule (default) to allow HTTP requests from lan1 to dmz. Responses to this request are allowed automatically. • a HTTP redirect rule to forward HTTP traffic from lan1 to proxy server A. For HTTP traffic between dmz and wan1: • a from DMZ to WAN firewall rule (default) to allow HTTP requests from dmz to wan1. Responses to these requests are allowed automatically. • a policy route to forward HTTP traffic from proxy server A to the Internet. Finding Out More See Section 6.6.10 on page 101 for related information on these screens. 19.2 The HTTP Redirect Screen To configure redirection of a HTTP request to a proxy server, click Configuration > Network > HTTP Redirect. This screen displays the summary of the HTTP redirect rules. 332 ISG50 User's Guide