This paper describes a novel cyber attack-resilient server inspired by the concept of biological diversity. The server consists of several virtual machines running different operating systems and different implementations of the same server protocol specification. This approach is based on the observation that not all implementations are affected by the same vulnerability, except for vulnerabilities in specifications and on shared libraries. A prototype system was built and tested to evaluate the continuity of the service. The results showed that, by exploiting a vulnerability, the prototype system could suppress downtime of the DNS service to less than 4 s without false positives.