To restrict internal LAN users from access to certain sites on the Internet, you can use the content filtering and web component blocking features of the VPN firewall. By default, these features are disabled; all requested traffic from any website is allowed. If you enable one or more of these features and users try to access a blocked site, they see a “Blocked by NETGEAR” message.
Several types of blocking are available:
• Web component blocking. You can block the following web component types: proxy, Java, ActiveX, and cookies. Even sites that are listed in the Trusted Domains table are subject to web component blocking when the blocking of a particular web component is enabled.
- Proxy. A proxy server (or simply, proxy) allows computers to route connections to other computers through the proxy, thus circumventing certain firewall rules. For example, if connections to a specific IP address are blocked by a firewall rule, the requests can be routed through a proxy that is not blocked by the rule, rendering the restriction ineffective. Enabling this feature blocks proxy servers.
- Java. Blocks Java applets from being downloaded from pages that contain them. Java applets are small programs embedded in web pages that enable dynamic functionality of the page. A malicious applet can be used to compromise or infect computers. Enabling this setting blocks Java applets from being downloaded. - ActiveX. Similar to Java applets, ActiveX controls are installed on a Windows computer running Internet Explorer. A malicious ActiveX control can be used to compromise or infect computers. Enabling this setting blocks ActiveX applets from being downloaded.
- Cookies. Cookies are used to store session information by websites that usually require login. However, several websites use cookies to store tracking information and browsing habits. Enabling this option blocks cookies from being created by a website.
Note: Many websites require that cookies be accepted for the site to be accessed correctly. Blocking cookies might interfere with useful functions provided by these websites.
• Keyword blocking(domain name blocking). You can specify up to 32 words to block. If any of these words appear in the website name (URL) or in a newsgroup name, the website or newsgroup is blocked by the VPN firewall.
You can apply the keywords to one or more LAN groups. Requests from the computers in the groups are blocked where keyword blocking has been enabled. Blocking does not occur for the computers in the groups where keyword blocking has been disabled. You can bypass keyword blocking for trusted domains by adding the exact matching domain to the Trusted Domains table. Access to the domains or keywords on this list by computers in the groups for which keyword blocking has been enabled is allowed without any blocking.
Keyword application examples:
• If the keyword “xxx” is specified, the URL http://www.companycom/xxx.html is blocked, as is the newsgroup alt.pictures.xxx.
• If the keyword “.com” is specified, only websites with other domain suffixes (such as .edu, .org, or .gov) can be viewed.
• If you wish to block all Internet browsing access, enter . (period) as the keyword. To enable and configure content filtering:
1. Select Security > Content Filtering. The Block Sites screen displays. (The following figure shows some examples.)
3. In the Web Components section of the screen, select the components that you want to block (by default, none of these components are blocked, that is, none of these check boxes are selected):
• Proxy. Blocks proxy servers.
• Java. Blocks Java applets from being downloaded. • ActiveX. Blocks ActiveX applets from being downloaded. • Cookies. Blocks cookies from being created by a website.
These components are described in the introduction of this section on page 186.
4. Click Apply to enable content filtering and blocking of the selected web components. The screen controls are activated.
To apply keyword blocking to LAN groups:
1. In the Apply Keyword Blocking to section of the screen, select the check boxes for the groups to which you want to apply keyword blocking, or click the Select All button to select all groups.
2. To activate keyword blocking for these groups, click the Enable button. To deactivate keyword blocking for the selected groups, click the Disable button.
Note: If you changed the LAN group names on the Edit Group Names screen (see Change Group Names in the Network Database on page100), the new names are displayed on the Block Sites screen.
To build your list of blocked keywords or blocked domain names:
1. In the Add Blocked Keyword section of the screen, in the Blocked Keyword field, enter a keyword or domain name.
2. After each entry, click the Add table button. The keyword or domain name is added to the Blocked Keywords table.
To edit an entry, click the Edit table button in the Action column to the right of the entry. To build your list of trusted domains:
1. In the Add Trusted Domain section of the screen, in the Trusted Domains field, enter a domain name.
2. After each entry, click the Add table button. The domain name is added to the Trusted Domains table.
To edit an entry, click the Edit table button in the Action column to the right of the entry.