403 error allocated to /24 prefix from ISP

Question

Hi.

We have issues with connectivity to multiple sites hosted to Azure services; however, we have noticed the issues are associated to /24 preffix(Colombia), and no other preffixes.

Specific error: Microsoft-Azure-Application-Gateway/v2

Regards.

Answer 1

Hello Redes Sistemas

Azure 403 Forbidden errors are access denial messages that occur when a user or application attempts to perform an action without proper permissions.

There could be multiple reasons of 403 errors:

• Network Security Groups (NSGs) are another frequent source of 403 errors. While essential for security, overly restrictive NSG rules can inadvertently block legitimate traffic. Some organizations accidentally block all inbound traffic to their Azure StaticWeb Apps, resulting in 403 errors for every user attempt. Careful review of NSG rules and use of Azure Network Watcher to visualize and troubleshoot network configurations can prevent these issues.
• Reach out to your ISP to see if they are aware of any issues or restrictions on this prefix. Test connection using tracert(traceroute) utility
• Contact Azure support for assistance. They might be able to provide a solution specific to your situation.