ZyXEL Communications 200 Series 用户手册

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页码 902
Chapter 17 HTTP Redirect
ZyWALL USG 100/200 Series User’s Guide
322
17.1.2  What You Need to Know About HTTP Redirect
Web Proxy Server
A proxy server helps client devices make indirect requests to access the Internet or outside 
network resources/services. A proxy server can act as a firewall or an ALG (application layer 
gateway) between the private network and the Internet or other networks. It also keeps hackers 
from knowing internal IP addresses.
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:
Firewall
Application Patrol 
HTTP Redirect
Policy Route 
Even if you set a policy route to the same incoming interface and service as a HTTP redirect 
rule, the ZyWALL 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 
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.
• an application patrol rule to allow HTTP traffic between lan1 and dmz.
• 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 request from dmz to wan1
Responses to this request are allowed automatically.
• a application patrol rule to allow HTTP traffic between dmz and wan1.
• a policy route to forward HTTP traffic from proxy server A to the Internet.
Finding Out More
See 
 for related information on these screens.
17.2  The HTTP Redirect Screen
To configure redirection of a HTTP request to a proxy server, click Network > HTTP 
Redirect
. This screen displays the summary of the HTTP redirect rules.