DNS (Domain Name System) – a fundamental, decentralised, hierarchically organised Internet service, which permits the translation of textual identifiers into numerical ones and vice versa. Internet communication is based on hard-to-remember numerical IP addresses, and DNS simplifies this for humans, allowing the use of domain names to identify devices on the Internet.
DNS server – a device which supplies the corresponding IP address for a requested textual address (as defined by the Internet domain name), allowing communication and the exchange of data on the network.
DNSSEC (DNS Security Extensions) – a system of security standards which facilitates the verification of the integrity of data in the DNS system.