OpenDNS is an American company providing Domain Name System resolution services—with features such as phishing protection, optional content filtering, and DNS lookup in its DNS servers—and a cloud computing security product suite, Umbrella, designed to protect enterprise customers from malware, botnets, phishing, and targeted online attacks. The OpenDNS Global Network processes an estimated 100 billion DNS queries daily from 85 million users through 25 data centers worldwide.
On August 27, 2015, Cisco acquired OpenDNS for US$635 million in an all-cash transaction, plus retention-based incentives for OpenDNS. OpenDNS's business services were renamed Cisco Umbrella; home products retained the OpenDNS name. Cisco said that it intended to continue development of OpenDNS with its other cloud-based security products, and that it would continue its existing services.
Until June 2014, OpenDNS provided an ad-supported service and a paid advertisement-free service. The services are based on software proprietary to the company.