SmartCache is a DNS record handling technology invented by OpenDNS that allows users of our service to access websites even when they are inaccessible everywhere else on the internet.

Challenges with authoritative DNS outages

Authoritative DNS servers house the mappings between domains and IP addresses for all sites on the internet, so it can cause major issues with accessibility if there are outages, distributed denial of service (DDoS) attacks, or other failures. When incidents like this occur — which can be fairly common — our recursive DNS service eliminates the impact to end users through the use of our SmartCache technology.

How does it work?

SmartCache locates the last known good IP address for the domain, so whenever the authoritative servers are unavailable, OpenDNS will return the IP address and end users will be able to access the site — even if the rest of the internet cannot.