Verisign is an operator of critical infrastructure within the domain name system, or DNS. As the registry for some of the world's most popular TLDs, .com and .net, Verisign directs DNS resolvers to the appropriate registry where IP addresses are stored. Verisign's control over its TLDs is regulated by ICANN and the NTIA and are subject to contract renewal every six years. The company generates revenue through annual subscriptions allowing customers to use .com and .net as their TLD of choice for their respective websites.