You can implement whitelist filters both privately (on the client) and at the DNS level.

可以私下(在客户机上)和在DNS级别上实现白名单过滤。

youdao

If you just used the black and whitelist solution, the spam would most likely get through.

如果您仅使用黑名单和白名单解决方案，那么很可能无法过滤出这封垃圾邮件。

youdao

You can use the device whitelist cgroup to deny the container the ability to open the devices.

可以使用设备白名单cgroup拒绝容器打开设备。

youdao

They will use technology to "blacklist" robocaller phone numbers and "whitelist" numbers associated with acceptable incoming calls.

CNN: Two win contest aimed at blocking robocalls

Essentially a Mobile Device Management (MDM) app for parents, this would also let me create a whitelist of kid-safe apps, prevent or control any downloads and generally track their usage.

FORBES: Parents Need Mobile Device Management, Too

By simply visiting the Parents Portal on MEEPTablet.com from any device with a web browser (computer, smart phone, tablet), parents can not only hand-pick ("whitelist") which websites or keywords their kids have or don't have access to, but they can add words to the tablet's built-in "bad word" list so their child will not be able to search for those words or use them in the chat feature.

ENGADGET: Oregon Scientific MEEP! tablet ships for $150, gives kids a safe, exclamation-filled place to play