FortiGate
FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
ezhupa
Staff
Staff
Article Id 297956
Description This article describes that Web filter is not working on Google Chrome browsers, but is working well for others.
Scope FortiGate.
Solution

In some cases, users might experience the following issues: 
Webfilter is in place on a flow mode firewall policy on the FortiGate to block certain websites through a static URL filter. 

The websites are blocked when using Firefox or Edge browser, but it is possible to navigate to these websites when using Chrome. 

 

If experiencing this issue, there are 3 possible solutions:

  1. Manually update the IPS engine of the FortiGate in question following the below procedure: Technical Tip: How to manually upgrade the IPS Engine
    Open a ticket with Fortinet Support to get the latest IPS Engine and then update it manually. 
  2. Disable TLS 1.3 hybridized Kyber support on the Google Browser:
    Navigate to  chrome://flags/ 
    Search for TLS 1.3 hybridized Kyber support 
    Set the action to Disable 
  3. Set the firewall policy in proxy-based inspection

Additionally, when using flow-based inspection, review and make sure the "unsupported-ssl-cipher" is set to "block". 

 

config firewall ssl-ssh-profile

edit "profile-name"

config https

set unsupported-ssl-cipher block

end

end

 

The default behaviour of this option is to "bypass" the session when an unsupported cipher is detected. 

 

set unsupported-ssl-cipher ?
allow Bypass the session when the cipher is not supported.
block Block the session when the cipher is not supported.


The websites should be blocked and the web filter will work as expected.

 

Note:

It will be necessary to close and reopen the browser for the change to take place.