Whitelist

A whitelist is the inverse of a blocklist: instead of listing unwanted parties, it lists what's allowed through — your clients' numbers, your vendors' SMS senders, your partners' domains. In telephony, a listed number's call will never be filtered or labeled "likely spam," whatever the filter's statistical criteria say.

It cuts both ways for a local business. Inbound: the owner who adds their twenty best clients to a whitelist never loses their call to spam filtering, even when the filter errs. Outbound: your business number must avoid the opposite effect — being labeled spam because it's new or emits many short calls. Registering your traffic and keeping healthy calling habits is the best whitelist there is.