Most operators who run their own DNS services use BIND named, the most widely used DNS server software outside the world of the big registrars. BIND named can function as an (authoritative) name server and/or as a (caching) resolver. This article looks at the signing of a zone on an authoritative name server. The configuration of named as a DNSSEC validating resolver is dealt with in a separate article.
BIND's DNSSEC functionality has developed incrementally over the past few years, to become a mature feature of this DNS server software. Because of the incremental development, there are significant differences between successive (minor) versions.
Where possible and relevant, this article indicates the version from which the features described are supported. That is important mainly for users of enterprise platforms, which for stability and security reasons tend not to use the most recent software versions. There will also be cases where an existing BIND software installation has been upgraded by the package management system of the operating system, but the configuration in use is still based on an older version.
We nevertheless recommend using the most recent version of BIND that you can, if for no other reason than that each successive version has bug-fixes and security-fixes absent from the earlier versions.