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All glossary terms

Proxy & networking

NXDOMAIN

NXDOMAIN is a DNS response code indicating that the queried domain name does not exist in the relevant DNS namespace. It is different from an existing name that lacks a requested record type, and it describes a lookup result rather than an application-level HTTP error.

Also known as DNS name error.

Why it matters in practice

NXDOMAIN responses can occur because of a typo, stale configuration, an unregistered name, or a filtering policy that intentionally returns that code. Repeated failures may be useful operational telemetry, but the code alone does not explain why resolution failed. Resolver logs and the query path provide needed context.

Example

A client asks for a misspelled api.example.com name and receives NXDOMAIN because no such DNS name is registered.

Educational note

This definition is general information, not legal advice. It may omit facts that matter to a specific situation and does not establish or guarantee compliance.