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Chapter 36 Content Filtering
ZyWALL USG 2000 User’s Guide
618
Content Filtering Profiles
A content filtering profile conveniently stores your custom settings for the 
following features.
• Category-based Blocking
The ZyWALL can block access to particular categories of web site content, such 
as pornography or racial intolerance.
• Restrict Web Features
The ZyWALL can disable web proxies and block web features such as ActiveX 
controls, Java applets and cookies.
• Customize Web Site Access 
You can specify URLs to which the ZyWALL blocks access. You can alternatively 
block access to all URLs except ones that you specify. You can also have the 
ZyWALL block access to URLs that contain particular keywords. 
Content Filtering Configuration Guidelines
When the ZyWALL receives an HTTP request, the content filter searches for a 
policy that matches the source address and time (schedule). The content filter 
checks the policies in order (based on the policy numbers). When a matching 
policy is found, the content filter allows or blocks the request depending on the 
settings of the filtering profile specified by the policy. Some requests may not 
match any policy. The ZyWALL allows the request if the default policy is not set to 
block. The ZyWALL blocks the request if the default policy is set to block.
External Web Filtering Service 
When you register for and enable the external web filtering service, your ZyWALL 
accesses an external database that has millions of web sites categorized based on 
content. You can have the ZyWALL block, block and/or log access to web sites 
based on these categories. 
Keyword Blocking URL Checking
The ZyWALL checks the URL’s domain name (or IP address) and file path 
separately when performing keyword blocking. 
The URL’s domain name or IP address is the characters that come before the first 
slash in the URL. For example, with the URL 
www.zyxel.com.tw/news/
pressroom.php
, the domain name is 
www.zyxel.com.tw
.
The file path is the characters that come after the first slash in the URL. For 
example, with the URL 
www.zyxel.com.tw/news/pressroom.php
, the file path is 
news/pressroom.php
.