A whitelist is a list or register of entities (e.g. email addresses) that have been granted a particular privilege, service, access or recognition. If you’re using AFS to send invitations, you can create a whitelist of email addresses that specify the domains that trigger invites. This way, Trustpilot knows what emails are allowed to trigger invitations to your customers.
IP whitelisting is technically not possible with ANY Trustpilot service. The reason for this is that we use a cloud-based system, where IP addresses and ranges change dynamically all the time.