Technical Tip: Analyzing Website Access issue with HAR Log Tools

[acvaldez]

Description	This article describes how to use the HAR log to further check which destination address to focus on when encountering a website access issue.
Scope	FortiGate.
Solution	Diagram: Sample Scenario: This capture was taken in a lab environment just to show how to maximize the HAR log tool to see which IP to focus on in website access issues. Test machine (IP: 10.118.4.202) is experiencing slowness when accessing CoinMarketCap, while other websites (e.g., Google, YouTube) are working fine. Here is the approach to diagnose and resolve this issue: Open Chrome Developer Tools: Navigate to the Network tab: Ensure the Domain column is visible: Check the HAR log for unsuccessful traffic when the issue occurs. Analysis: From the HAR log, a JavaScript file from the domain cdn.cookielaw.org failed to load: Ping the domain cdn.cookielaw.org to obtain its IP address: Filter this IP address in FortiGate to observe how it is being handled: Resolution: In the lab FortiGate, filtering logs using the IP [104.19.177.52] showed that traffic to this IP was being blocked. Creat a policy in FortiGate to allow traffic to this IP. After implementing the policy, CoinMarketCap started working without any issues.