Addresses for VPN communication

To prevent conflict or overlap with internal ServiceNow networks or with another internal IP address schemes in your network, all tunneled traffic in the encryption domain must use non-RFC-1918 addresses on both sides of the tunnel.

ServiceNow provides a single IP address for the source of queries into your network. You must provide Network Address Translation (NAT), non-RFC-1918 addresses for each host that is integrating with your instance. These public addresses need to be owned by your organization. Third party addresses cannot be used inside tunnels. Additionally, the encryption domain must not contain the IP address of the VPN peer.