ICANN Acronyms and Terms
Type in the acronym or term you are looking for in the Search bar below.
In addition to English, translated versions of acronyms and terms are also available in Arabic, Chinese, French, Russian, and Spanish. Links for each language are located in the top right of the page.
Click the first letter of the term you are looking for to search alphabetically.
Do you have feedback on the definitions or the terms? Send us an email to: acronymsandterms@icann.org.
A
anycast instance
A server that responds to an anycast Internet Protocol (IP) address. With anycast routing, a server is replicated across multiple network locations. The servers are then assigned to the same anycast IP address. Each server assigned to that IP address is referred to as an anycast instance (or simply an instance). When a computer sends a message to an anycast IP address, Internet routers automatically direct the message to the nearest (in terms of routing distance) available instance of that server. Anycast routing helps reduce latency and improve reliability.
Many of the authoritative name servers in the Domain Name System use anycast routing.