What is my public IP address range of my LAN

Hi

I need to whitelist the public IP address range of my LAN.

Basically I have created a S2S VPN between my on premise environment and my azure network.

The VPN works and I can remote onto VMs from my LAN however I cannot browse storage accounts that are locked to VNETS.

This is because I need to whitelist the public IP address range coming from my VPN gateway. I don't know what this or how to get this?

Any ideas? I can whitelist the internal IP address range of my LAN.

Thanks