DNS server

In short: A DNS server answers questions about names and returns the matching IP address (e.g. emzett-digital.com → a number).

In more detail: DNS is spread across many servers. Two roles are distinguished: the recursive resolver, which your device asks, and the authoritative servers, which store the binding records for a domain.

In Depth

• Process: if needed the resolver asks the root servers, then the server for the ending (e.g. .com) and finally the domain’s authoritative server. It caches the result as long as the TTL allows.
• Which server is used? Usually the one assigned by the DHCP server, often your own router, which asks the provider onwards. Alternatives are public resolvers such as 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google).
• Port: 53 (UDP, TCP for large answers). Encrypted variants are DNS over HTTPS and DNS over TLS.
• Own server: companies run internal DNS servers for names inside their network.
• Testing: nslookup queries a DNS server directly.

See also: DNS, DNS records