IRONSIDES is an authoritative DNS server that is provably invulnerable to
many of the problems that plague other servers. It achieves this property
through the use of formal methods in its design, in particular the language
Ada and the SPARK formal methods tool set. Code validated in this way is
provably exception-free, contains no data flow errors, and terminates only
in the ways that its programmers explicitly say that it can. These are very
desirable properties from a computer security perspective.

IRONSIDES is not a complete implementation of DNS. In particular, it does
not support zone transfers or recursive queries. It does, however, support
a sufficient number of DNS records to be useful as an authoritative DNS
server for an enterprise.

WWW: http://ironsides.martincarlisle.com