Node.js DNS

Introduction:

DNS is a node module used to do name resolution facility which is provided by the operating system as well as used to do an actual DNS lookup.

Advantage
No need for memorising IP addresses – DNS servers provide a nifty solution of converting domain or subdomain names to IP addresses.

Example 1:

// Include 'dns' module and create its object
const dns = require('dns');

const website = 'geeksforgeeks.org';
// Call to lookup function of dns
dns.lookup(website, (err, address, family) => {
  console.log('address of %s is %j family: IPv%s',
           website, address, family);
});

// Execute using $ node <filename>

Output:

address of geeksforgeeks.org is "52.25.109.230" family: IPv4

Example 2:

// Include 'dns' module and create its object
var dns = require('dns');

// Call to reverse function along with lookup function.
dns.lookup('www.geeksforgeeks.org',
     function onLookup(err, address, family) {
    console.log('address:', address);
    dns.reverse(address, function (err, hostnames) {
      console.log('reverse for ' + address + ': '
             + JSON.stringify(hostnames));
   });
});

// Execute using $ node <filename>

Output:

address: 52.222.176.140
reverse for 52.222.176.140: ["server-52-222-176-140.bom52.r.cloudfront.net"]

Reference:
https://nodejs.org/docs/latest-v9.x/api/dns.html#dns_dns