ZyWALL 2 Series User’s Guide
Step 1. A computer sends an HTTP request to a web server.
Step 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 either blocks or forwards the request based on how you configure the category based content filtering.
The ZyWALL drops a URL record from the content filter cache after the content filter cache timeout period (default 30 minutes). All of the URL records are also cleared from the local cache when the ZyWALL reboots. You can use ip urlfilter webControl cache timeout on the command line to change the timeout period.
If the ZyWALL doesn’t have a record of the web site, it will query the external content filtering server and simultaneously send the request to the web server.
The external content filtering database may change a web site’s category or rate a previously uncategorized web site.
Step 3. The external content filtering server sends the category information back to the ZyWALL, which then either forwards or blocks the web content. The web site address is then also stored in the ZyWALL’s content filtering cache.
12.4 Checking Content Filtering Activation
After you register for content filtering, the web site displays a registration successful web page. This does not mean the content filtering is active yet. You need to wait up to ten minutes for the content filtering to be activated.
Since there will be no activation notice, do the following:
Step 1. Go to your device’s web configurator’s Content Filtering, Categories screen. Step 2. Select at least one category and click Apply.
Step 3. Enter a valid URL or IP address of a web site in the Test if Web site is blocked field and click the Test Against Internet Server button.
When content filtering is active, you should see an access blocked or access forwarded message. An error message displays if content filtering is not active.
12.5 Configuring for Registering and Categories
To register for and configure
Content Filtering Screens |