DNS filtering

DNS filtering is a URL filtering feature that

  • evaluates domain category and reputation early in URL transactions, when the browser looks up the domain name to get the IP address,

  • can often determine category and reputation of encrypted traffic without decryption, and

  • is enabled by default through the Enable reputation enforcement on DNS traffic option on the Advanced tab of each new access control policy.

DNS filtering behavior

DNS filtering slightly modifies URL filtering behavior and is applicable only when URL filtering is enabled and configured.

If DNS filtering cannot determine the URL of encrypted traffic, that traffic is processed using your configurations for encrypted traffic.