DNS filter blocks web browsing

[coolang]

Hi

I am currently using Fortinet V7.4.4 and recently encountered an issue where users connected to the WiFi1 network were unable to browse the web. However, there were no issues with web browsing when connected to the WiFi2 network.

After comparing the configurations of both WiFi networks, I noticed that the DNS filter was enabled on WiFi1. Disabling the DNS filter resolved the issue.

We haven’t made any configuration changes, so I’m curious—why would the DNS filter block web browsing?

[dingjerry_FTNT]

Hi @coolang ,

First of all, Fortinet is not a name for any product.  I believe that you are talking about FortiGate. Please use the correct product name.

And you did not share your DNS Filter configuration, I have no idea why it blocks web browsing.

So:

1) What URL did you get blocked?

2) What is the configuration for this URL in the DNS Filter?  Action with Allow or Block?

3) Did you get any block page with any message?

4) What is your DNS query traffic? I mean, does it pass through FortiGate?  If so, where is the DNS server?

[sjoshi]

Hi,

Please check what is the error the user was getting in his browser

Verify the DNS logs and see what is blocking

https://docs.fortinet.com/document/fortigate/7.6.0/administration-guide/605868/dns-filter

You need to allow the required website even from the dns filter

[coolang]

Hi sjoshi

Can you please provide guide on how to find the DNS logs?

Thanks

[sjoshi]

Please refer DNS query logs

Log & Report > Security Events > DNS Query