Before you obtain the IP address of the load generator, you must create a stress testing scenario in the Performance Testing Service (PTS) console and start the stress testing. For more information, see Create a scenario.
If you have created a stress testing scenario, you can choose in the left-side navigation pane. On the Scenarios page, find the scenario that you want to start and click Start in the Actions column. On the Executing Test page, click Load Generator Monitoring to view the IP address of the load generator.

What to do next
After you obtain the IP address of the load generator, you can add the IP address to a whitelist. This way, you can enable policies and start stress testing only for the IP address.
Configure protection rules for the whitelist module of Web Application Firewall (WAF) to prevent stress testing traffic from being blocked. For more information, see Configure protection rules for the whitelist module to allow specific requests.