We present D3NS, a system to replace the current top level DNS system and certificate authorities, offering increased scalability, security and robustness. D3NS is based on a distributed hash table and utilizes a domain name ownership system based on the Bitcoin blockchain. It addresses previous criticism that a DHT would not suffice as a DNS replacement. D3NS provides solutions to current DNS vulnerabilities such as DDOS attacks, DNS spoofing and censorship by local governments. D3NS eliminates the need for certificate authorities by providing a decentralized authenticated record of domain name ownership. Unlike previous DNS replacement proposals, D3NS is reverse compatible with DNS and allows for incremental implementation within the current system.