ZyXEL Communications ZyWall USG20-VPN, Руководство пользователя

Страница: 264 / 683

Chapter 13 HTTP Redirect
USG20(W)-VPN Series User’s Guide
264
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, Security Policy and Policy Route
With HTTP redirect, the relevant packet flow for HTTP traffic is:
1
Security Policy
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 USG checks the HTTP redirect rules first and forwards HTTP traffic to a proxy server if matched.
You need to make sure there is no security policy(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 173 on page 263 work, make sure you have the
following settings.
For HTTP traffic between lan1 and dmz :
• a from LAN1 to DMZ security policy (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 security policy (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.
13.2 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.
Note: You can configure up to one HTTP redirect rule for each (incoming) interface.