This article shows how to find the GlobalProtect Client IP range based on PA-850 firewall.
1. Login to the web interface, for example https://192.168.11.11
2. Go to Network > GlobalProtect > Gateways
3. Click on the GlobalProtect name to open it.
4. Click on Agent and then Client Settings. The IP pool is the VPN Client IP range.
Please view this step by step video: