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Node.js DNS

The dns module enables name resolution. For example, use it to look up IP addresses of host names.

Syntax

The syntax for including the DNS module in your application:

var dns = require('dns');

DNS Methods

Let's see a list of commonly used DNS methods:

Method Description
getServers() Returns an array containing all IP addresses belonging to the current server
lookup() Looks up a hostname. A callback function contains information about the hostname, including it's IP address
lookupService() Looks up a address and port. A callback function contains information about the address, such as the hostname
resolve() Returns an array of record types belonging to the specified hostname
resolve4() Looks up an IPv4 address. The callback function includes an array of IPv4 addresses
resolve6() Looks up an IPv6 address. The callback function includes an array of IPv6 addresses
resolveCname() Looks up CNAME records for the specified hostname. The callback function includes an array of available domains for the hostname
resolveMx() Looks up mail exchange records for the specified hostname.
resolveNaptr() Looks up regular expression based records for the specified hostname.
resolveNs() Looks up name server records for the specified hostname.
resolveSoa() Looks up a start of authority record for the specified hostname.
resolveSrv() Looks up service records for the specified hostname.
resolvePtr() Looks up pointer records for the specified hostname.
resolveTxt() Looks up text query records for the specified hostname.
reverse() Reverses an IP address into an array of hostnames
setServers() Sets the IP addresses of the servers

 

Examples

 

const dns = require('dns');  
dns.lookup('www.google.com', (err, addresses, family) => {  
  console.log('addresses:', addresses);   
});  
var dns = require('dns');
var demo = dns.lookupService('127.0.0.1', 21, (err, hostname, service) => {
console.log(hostname, service);
});
const dns = require('dns');
const rrtype="A";
dns.resolve('www.google.com', rrtype, (err,
records) => console.log('records: %j', records));
const rrtype1="TXT";
dns.resolve('www.google.com', rrtype1, (err,
records) => console.log('records: %j', records));
const rrtype2="NS";
dns.resolve('www.google.com', rrtype2, (err, 
records) => console.log('records: %j', records));

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