MaxMind offers 22 different risk ratings and scores to enable WHMCS and you to decide whether an order is fraudulent. For details about each of the individual checks, see Fraud Detection Manual MaxMind allows you to do both basic fraud checks and phone verifications. WHMCS offers free MaxMind minFraud service if you have a license purchased directly through them.
The score rating that you want to start blocking orders at is up to you but MaxMind recommend 2.5. For more information, see Web Services Score
Note: WHMCS uses the older MaxMind 0-10 score scale, rather than their 0-100 scale.
Server Modules
cPanel/WHM - DirectAdmin - Plesk - Helm 3 - Helm 4 - Ensim - InterWorx - DotNetPanel
Lxadmin - Virtualmin Pro - XPanel - HyperVM - FluidVM - SolusVM - Cloudmin - WHMSonic
CentovaCast - SCPanel - CastControl - GameCP - TCAdmin - Reseller Central - Auto Release
Registrar Modules
Enom - ResellerClub - Nominet - OpenSRS - ResellOne - OnlineNIC - PlanetDomain
DistributeIT - TPPInternet - RegisterFly - Stargate - Namecheap - NetEarthOne
12Register - Registercom - DotDNS - WebNIC - Dot.TK - HexoNet - Realtime Register
Fraud Modules
MaxMind - VariLogiX FraudCall - Telesign
Selected Gateway Modules
Payflow Pro - Authorize.net - BluePay - Quantum Gateway - eWay - eProcessingNetwork
InternetSecure - LinkPoint - SecPay - ProtX - PSIGate - WorldPay Invisible - NaviGate
Merchant Partners - PayOffline - Offline Credit Card - PayPal - ChronoPay - 2CheckOut - Google CheckOut
WorldPay - E-Gold - Gate2Shop - F2B - PagSeguro - NoChex - AlertPay - ProtX VPS Form - Paymex
CashU - Liberty Reserve - StormPay - Paymate AU and NZ - Payson - BRPay - Boleto - MoneyBookers
PayOffline - Mail In Payment - Bank Transfer - USA ePay - Pay Junction - PayPal Website Payments Pro