A whitelist or allowlist is a list or register of entities that are being provided a particular privilege, service, mobility, access or recognition.
[citation needed][2] Non-commercial whitelists are operated by various non-profit organizations, ISPs, and others interested in blocking spam.
Rather than paying fees, the sender must pass a series of tests; for example, their email server must not be an open relay and have a static IP address.
[citation needed] One approach in combating viruses and malware is to whitelist software which is considered safe to run, blocking all others.
[citation needed] Leading providers of application whitelisting technology include Bit9, Velox, McAfee, Lumension, ThreatLocker, Airlock Digital and SMAC.