This report by Catherine Herridge of Fox News featured input and commentary by Bob Gourley, including context on what it means to whitelist:
“Think of whitelisting like a bouncer in the VIP line at the party. If you are on the list you get in, if you are not, you get bounced to the pavement,” said Bob Gourley, former chief technology officer (CTO) for the DIA.”
“Whitelisting happens by design. The IT professionals who whitelist devices at places like the White House only add the email addresses authorized by management. To do otherwise would be to violate policy in ways that could introduce threats to the system,” he added.
For more see: Fox News