Technical Tip: How to allow or exempt a URL in a blocked category

[btie]

Description

This article provides an example of how to create a URL filter rule to 'Allow' or 'Exempt' a particular URL from a 'Blocked' Category in FortiGuard Web Filtering.

Using Regex - Regular Expression.

Scope

FortiGate.

Solution

Web-based Manager (GUI).

• Go to Security Profiles -> Web Filter -> Static URL Filter and enable URL Filter.
• Select 'Create New', or select an already available list.
• Select 'Create New', to create an entry for each of the following exempt rules.
  

URL= .*\.example\.com.*
Type= regex
Action =allow

URL= .*\.fortinet\.com.*
Type= regex
Action =exempt

Comand Line Interface (CLI).

config webfilter profile
    edit "URL_Filter"
config web
    set urlfilter-table 1  <----- The ID as below.
end  

config webfilter urlfilter
    edit 1  <---
        set name "Static URL Filter - URL_Filter Web Filter Profile"
config entrie
    edit 1
        set url ".*\\.example\\.com.*"  <----- Double escape character '\' , one of them is added automatically by FortiGate, for the same reason.
        set type regex
        set action allow
    next
        edit 2
            set url ".*\\.fortinet\\.com.*"
            set type regex
        next
    end
next
end

Explanation regarding regex special characters use:

To match a special character such as '.' or ‘*’ use the escape character ‘\’.  For example, to match fortinet.com the regular expression should be fortinet\.com.

In Perl regular expressions, ‘*’ means match 0 or more times of the character before it, not 0 or more times of any character. For example, forti*.com matches fortiiii.com but does not match fortinet.com.

To match any character 0 or more times, use ‘.*’ where ‘.’ means any character, and the ‘*’ means 0 or more times. For example, the wildcard match pattern forti*.com should therefore be forti.*\.com.