General Screen; Figure 187 Content Filtering Lookup Procedure - ZyXEL Communications 5 Series User Manual

Chapter 17 Content Filtering Screens

Figure 187 Content Filtering Lookup Procedure

1 A computer behind the ZyWALL tries to access a web site.
2 The ZyWALL looks up the web site in its cache. If an attempt to access the web site was
made in the past, a record of that web site's category will be in the ZyWALL's cache.
The ZyWALL blocks, blocks and logs or just logs the request based on your
configuration.
3 Use the CONTENT FILTER Cache screen to configure how long a web site address
remains in the cache as well as view those web site addresses (see
346). All of the web site address records are also cleared from the local cache when the
ZyWALL restarts.
4 If the ZyWALL has no record of the web site, it will query the external content filtering
database and simultaneously send the request to the web server.
The external content filtering database may change a web site's category or categorize a
previously uncategorized web site.
5 The external content filtering server sends the category information back to the
ZyWALL, which then blocks and/or logs access to the web site. The web site's address
and category are then stored in the ZyWALL's content filtering cache.
Policies
Content filtering policies allow you to have different content filtering settings for different
users or groups of users. For example, you may want to block most employees from accessing
finance or stock websites, but allow the finance department to access these. You can set the
ZyWALL to use external database content filtering and select which web site categories to
block and/or log.
Finding Out More
• See Section 5.6 on page 133

17.2 General Screen

Click SECURITY > CONTENT FILTER to open the General screen. Use this screen to
enable content filtering and configure general settings.
You must register for external content filtering before you can use it.
328
for a tutorial on content filtering.
ZyWALL 5/35/70 Series User's Guide
Section 17.9 on page