Web content filter

You can control access to web content by blocking webpages containing specific words or patterns. This helps to prevent access to pages with questionable material. You can specify words, phrases, patterns, wildcards, and regular expressions to match content on webpages. You can use multiple web content filter lists and select the best one for each web filter profile. The maximum number of web content patterns in a list is 5000.

When configuring a web content filter list, the following patterns are available:

Web content pattern type

Description

Wildcard

Use this setting to block or exempt one word or text strings of up to 80 characters. You can also use wildcard symbols such as ? or * to represent one or more characters. For example, a wildcard expression forti*.com matches fortinet.com and fortiguard.com. The * represents any character appearing any number of times.

Regular expression

Use this setting to block or exempt patterns of regular expressions that use some of the same symbols as wildcard expressions, but for different purposes. In regular expressions, * represents the character before the symbol. For example, forti*.com matches fortiii.com but not fortinet.com or fortiice.com. In this case, the symbol * represents i appearing any number of times.

Content evaluation

The web content filter scans the content of every webpage that is accepted by a firewall policy. The system administrator can specify banned words and phrases and attach a numerical value (or score) to the importance of those words and phrases. When the web content filter scan detects banned content, it adds the scores of banned words and phrases found on that page. If the sum is higher than a threshold set in the web filter profile, the FortiGate blocks the page.

The default score for web content filter is 10 and the default threshold is 10. This means that by default, a webpage is blocked by a single match. These settings can only be configured in the CLI.

Banned words or phrases are evaluated according to the following rules:

  • The score for each word or phrase is cou