Mainly to prevent Affiliates from Cheating.
FuseClick allows to add server IPs of Advertisers, for the global set of white list and the white list for advertisers. When the advertiser system receives a conversion, advertiser will call the postback URL of FuseClick and sends the result of conversion to FuseClick. When FuseClick receives postback URL request call from the advertiser server, it will first check if the server IP address is in the whitelist or not. If the IP is found in the Whitelist, it regarded as a valid advertisers call. Otherwise, the conversion will be marked as rejected in the conversion report.