azure web app vnet integration and network security group(app service 403 forbidden)

there are a few potential issues to consider:

Verify NSG rules: Double-check your NSG rules to ensure that they allow inbound traffic from the necessary sources, such as your local system's public IP address and any required outbound IPs. Make sure that you have configured the rules correctly, including the correct protocol (e.g., HTTP or HTTPS) and port.

Check subnet association: Ensure that your Azure Web App is associated with the correct subnet within your virtual network. If the subnet association is not configured properly, the network traffic might not flow through the desired path, leading to access issues.

Check network route settings: Confirm that your virtual network is correctly configured to route traffic to and from your Azure Web App. Review the routes within the virtual network and ensure they are directing traffic appropriately.

Investigate network connectivity: Check the network connectivity between your local system and the Azure Web App. Ensure that there are no firewall rules or network restrictions on your local network that could be blocking the traffic. Additionally, validate that the necessary network ports are open for the desired protocol (e.g., TCP port 80 for HTTP).

Debug application-specific issues: If the above steps don't resolve the issue, there might be application-specific restrictions or authorization settings causing the 403 Forbidden error. Review your application's authentication and authorization settings, including any role-based access controls or authentication providers, to ensure they are properly configured.

Monitor diagnostic logs: Enable diagnostic logging for your Azure Web App and review the logs to gather more information about the 403 Forbidden error. The logs can provide insights into any specific error messages or issues that might help in troubleshooting the problem.

If you have tried these steps and are still experiencing the issue, it would be beneficial to provide additional details about your configuration and any relevant error messages for further assistance.

@Anonymous

Thanks for reaching here! It seems like you have configured the network isolation for your App Service and added the VNet rule in the access restriction. However, you are still getting a 403 error when browsing the App Service.

To troubleshoot this issue, you can follow the below steps:

1. Check if the VNet is properly configured and the NSG rules are correctly applied to the subnet containing the App Service. You can verify this by checking the NSG flow logs. See- https://learn.microsoft.com/en-us/troubleshoot/azure/app-service/troubleshoot-vnet-integration-apps
2. Check if the App Service is properly configured to use the VNet. You can verify this by checking the App Service's Networking settings.
3. Check if the App Service is properly configured to use the access restriction rule. You can verify this by checking the App Service's Access Restrictions settings.
4. Check if the IP address of your local system is correctly added to the access restriction rule. You can verify this by checking the Access Restrictions settings.

Please let us know if further query or issue remains.

Did you enable Service endpoint or private endpoint on the App Service. If yes, you will need to make enable the service endpoint in Azure VNET to let resources in the VNET to access the Web App.

In case of Private endpoint, you will need to let the PE configured and have IP connectivity to the PE from the VNET to access the Web App.

Regards,

Karthik Srinivas