Node.js DNS

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 memorizing IP addresses – DNS servers provide a nifty solution for converting domain or subdomain names to IP addresses. 

Example 1: In this example, we will print the address of GeeksforGeeks on the console.

javascript

// 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: In this example, we will print the address of the GeeksforGeeks.

javascript

// Include 'dns' module and create its object
const 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