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Firewall indirect service issue

Forum|Forum|1 year ago
December 3, 2024
2 replies
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Hello, I’m experiencing an issue with my firewall. A service used within a website is fetching image files from its own server. Due to a problem with the firewall, I can't see these images. From the firewall logs, I see that there is no response from the other side. However, when I use my mobile internet, I can access both the website and the images fetched by the service. I’ve allowed access to the services the website connects to through Google Chrome in the firewall, but the issue persists.

FortiGate

Staff

Hi Renra,

Create a firewall policy allowing specific users to access ALL and then check.

Review the forwarding traffic logs and examine the action field.

In test plain policy modify the MSS to 1300 and then check in the incognito mode.

config firewall policy
edit <policy id>
set tcp-mss-sender <mss value>
set tcp-mss-receiver <mss value>
end

Perform DNS lookup on the internal host machine for the problematic website to verify it is resolving and take note of the IP address.

Once the DNS lookup happens, focus on traffic flow.

If both local DNS and global DNS have the same resolution, run the following sniffers:

# diag sniffer packet any 'host a.b.c.d and x.x.x.x' 6 0 a

Please refer to the below document for more information:
https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-website-is-not-reachable/ta-p/210201

If you have found a solution, please like and accept it to make it easily accessible to others.

Regards,
Aman

Staff

Hi renra,

You can do the inspect element and collect the HAR logs and see what domain are being blocked

https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-How-to-collect-HAR-files/ta-p/191358

Thanks, Salon