If you want to use availability tests on internal servers that run behind a firewall, you have two possible solutions: public availability test enablement and disconnected/no ingress scenarios.
Public availability test enablement
If you don't want to allow any ingress to your environment, use the method in the Disconnected or no ingress scenarios section.
Ensure you have a public DNS record for your internal website. The test will fail if the DNS can't be resolved. For more information, see Create a custom domain name for internal application.
Configure your firewall to permit incoming requests from our service.
Service tags are a simple way to enable Azure services without having to authorize individual IPs or maintain an up-to-date list. Service tags can be used across Azure Firewall and network security groups to allow our service access. The service tag ApplicationInsightsAvailability is dedicated to our ping testing service, which covers both URL ping tests and Standard availability tests.
If you're using Azure network security groups, go to your network security group resource and under Settings, select inbound security rules. Then select Add.
Next, select Service Tag as the source and select ApplicationInsightsAvailability as the source service tag. Use open ports 80 (http) and 443 (https) for incoming traffic from the service tag.
If your endpoints are hosted outside of Azure or service tags aren't available for your scenario, you'll need to individually allowlist the IP addresses of our web test agents. You can query the IP ranges directly from PowerShell, the Azure CLI, or a REST call by using the Service Tag API. You can also download a JSON file to get a list of current service tags with IP address details.
In your network security group resource, under Settings, select inbound security rules. Then select Add.
Next, select IP Addresses as your source. Then add your IP addresses in a comma-delimited list in source IP address/CIRD ranges.
Disconnected or no ingress scenarios
To use this method, your test server must have outgoing access to the Application Insights ingestion endpoint. This is a much lower security risk than the alternative of permitting incoming requests. The results will appear in the availability web tests tab with a simplified experience from what is available for tests created via the Azure portal. Custom availability tests will also appear as availability results in Analytics, Search, and Metrics.
- Connect your Application Insights resource and disconnected environment by using Azure Private Link.
- Write custom code to periodically test your internal server or endpoints. You can run the code by using Azure Functions or a background process on a test server behind your firewall. Your test process can send its results to Application Insights by using the
TrackAvailability()API in the core SDK package.
For more information, see the troubleshooting article.