node:dns

Node.js dns module, resolvable via both ESM import and CommonJS require, plus the promise API at node:dns/promises. Both are registered built-ins backed by a native resolver.

Functions

Function	Description
`lookup(hostname[, options], callback)`	Resolve a hostname to an address using the system resolver order.
`lookupService(address, port, callback)`	Reverse-resolve an address and port to a hostname and service.
`getDefaultResultOrder()`	Return the current default address ordering.
`setDefaultResultOrder(order)`	Set the default address ordering (`ipv4first` / `verbatim`).
`reverse(ip, callback)`	Reverse-resolve an IP address to an array of hostnames.

Record resolution

The resolve* family queries specific DNS record types:

Function	Record type
`resolve4(hostname, cb)`	`A`
`resolve6(hostname, cb)`	`AAAA`
`resolveCname(hostname, cb)`	`CNAME`
`resolveNs(hostname, cb)`	`NS`
`resolvePtr(hostname, cb)`	`PTR`
`resolveMx(hostname, cb)`	`MX`
`resolveSrv(hostname, cb)`	`SRV`
`resolveCaa(hostname, cb)`	`CAA`
`resolveNaptr(hostname, cb)`	`NAPTR`
`resolveTlsa(hostname, cb)`	`TLSA`
`resolveTxt(hostname, cb)`	`TXT`
`resolveSoa(hostname, cb)`	`SOA`
`resolveAny(hostname, cb)`	multiple record types (`ANY`)

The `Resolver` class

new dns.Resolver([options]) creates an independent resolver exposing the same resolve* methods, so options can be scoped per instance rather than shared with the default resolver. options accepts timeout (in milliseconds) and tries. resolver.cancel() cancels all outstanding queries on that resolver.

> resolver.setLocalAddress() is not implemented.

Error codes

node:dns exports the standard DNS error-code constants — such as NODATA, NOTFOUND, SERVFAIL, REFUSED, and CANCELLED — for comparing against a failed query's err.code. These constants are exported from node:dns only, not from node:dns/promises.

Promises API

node:dns/promises exposes the same surface as promise-returning functions instead of callbacks, as in Node:

import dns from "node:dns/promises";

const addresses = await dns.resolve4("example.com");