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lookupService - node__dns.d.ts - Node documentation
function lookupService

Usage in Deno

```typescript import { lookupService } from "node:node__dns.d.ts"; ```
lookupService(
address: string,
port: number,
callback: (
err: ErrnoException | null,
hostname: string,
service: string,
) => void
,
): void
Resolves the given `address` and `port` into a host name and service using the operating system's underlying `getnameinfo` implementation. If `address` is not a valid IP address, a `TypeError` will be thrown. The `port` will be coerced to a number. If it is not a legal port, a `TypeError` will be thrown. On an error, `err` is an [`Error`](https://nodejs.org/docs/latest-v22.x/api/errors.html#class-error) object, where `err.code` is the error code. ```js import dns from 'node:dns'; dns.lookupService('127.0.0.1', 22, (err, hostname, service) => { console.log(hostname, service); // Prints: localhost ssh }); ``` If this method is invoked as its [util.promisify()](https://nodejs.org/docs/latest-v22.x/api/util.html#utilpromisifyoriginal) ed version, it returns a `Promise` for an `Object` with `hostname` and `service` properties.

Parameters

address: string
port: number
callback: (
err: ErrnoException | null,
hostname: string,
service: string,
) => void

Return Type

void