Java – Get nameservers of a website

In this tutorial, we will show you how to get the nameservers of a website using Java + dig command.

1. Using Dig Command

1.1 On Linux, we can use dig command to query a DNS lookup of a website, for example :

$ dig any mkyong.com

//...
mkyong.com.             299     IN      A       162.159.x.x
mkyong.com.             299     IN      A       198.41.x.x
mkyong.com.             299     IN      MX      10 aspmx2.googlemail.com.
mkyong.com.             299     IN      MX      10 aspmx3.googlemail.com.
mkyong.com.             299     IN      MX      1 aspmx.l.google.com.
mkyong.com.             299     IN      MX      5 alt1.aspmx.l.google.com.
mkyong.com.             299     IN      MX      5 alt2.aspmx.l.google.com.
mkyong.com.             21599   IN      NS      max.ns.cloudflare.com.
mkyong.com.             21599   IN      NS      erin.ns.cloudflare.com.

;; Query time: 246 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Tue Mar 18 08:35:24 Malay Peninsula Standard Time 2014
;; MSG SIZE  rcvd: 387

P.S The dig is a built-in command on *nix, no need to install.

1.2 On Windows, you need to install the BIND package (a zip file) from isc.org, and the dig command is inside the zip file. After extracting the downloaded zip file, set the “bind” folder to the environment variable, so that you can use the dig command everywhere.

C:\> dig +short NS mkyong.com
max.ns.cloudflare.com.
erin.ns.cloudflare.com.

2. Java DNS Example

In Java, we can call the external dig command to get the name servers easily.

package com.mkyong.shell;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class ShellCommand {

	public static void main(String args[]) {

		ShellCommand shell = new ShellCommand();

		String result = shell.run("dig +short NS mkyong.com");
		System.out.println(result);

	}

	public String run(String command) {

		StringBuilder sb = new StringBuilder();
		BufferedReader reader = null;
		Process p;

		try {
			p = Runtime.getRuntime().exec(command);
			p.waitFor();
			reader = new BufferedReader(
				new InputStreamReader(p.getInputStream()));

			String line = "";
			while ((line = reader.readLine()) != null) {
				sb.append(line + "\n");
			}

		} catch (Exception e) {
			e.printStackTrace();
		} finally {

			if (reader != null) {
				try {
					reader.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}

		return sb.toString();

	}

}

Output

max.ns.cloudflare.com.
erin.ns.cloudflare.com.

3. Get mail servers

In addition, you can use “MX” to get mail servers.

C:\> dig +short MX mkyong.com

10 aspmx2.googlemail.com.
5 alt2.aspmx.l.google.com.
5 alt1.aspmx.l.google.com.
1 aspmx.l.google.com.
10 aspmx3.googlemail.com.

References

1. 10 Linux DIG Command Examples for DNS Lookup
2. Wikipedia : Dig (command)
3. DNSJava official site
4. How To Execute Shell Command From Java