The present invention relates to an enhanced DNS resolver architecture configured to operate in high availability environments, such as the Internet. Specifically, the DNS resolver code of the present invention may be implemented by a storage operating system in a filer. The resolver code modifies a conventional resolver algorithm so as to reduce the time necessary to map IP addresses to alphanumeric domain names and vice versa. Advantageously, the enhanced resolver code keeps track of non-responsive or "dead" DNS servers as well as non-resolvable or "bad" domain names and IP addresses.