Every Service Plan can make requests to the internet, for example, calling a public REST service.
All outbound requests are made through an egress-only internet connection which does not identify the public IP address of your Service Plan. This means that a third-party cannot use the source of this connection to attempt to access your Service Plan.
Should you need to add your Service Plan to a whitelist, a list of IP address that the Service Plan could use can be obtained by contacting support. This includes whitelists you may configure when using Gateway REST services or Gateway Tunnels.