dns.lookupService

History

dns.lookupService(address, port, callback): void

Attributes

address:string

port:number

callback:Function

err:Error

hostname:string

e.g. example.com

service:string

e.g. http

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 object, where err.code is the error code.

import dns from 'node:dns';
dns.lookupService('127.0.0.1', 22, (err, hostname, service) => {
  console.log(hostname, service);
  // Prints: localhost ssh
});

JavaScript

const dns = require('node:dns');
dns.lookupService('127.0.0.1', 22, (err, hostname, service) => {
  console.log(hostname, service);
  // Prints: localhost ssh
});

JavaScript

If this method is invoked as its util.promisify()ed version, it returns a Promise for an Object with hostname and service properties.