IP Address from hostname (loopback, local & standard hosts) in java (example)

Leave a Comment / By /
  • Given hostname in java, we would like to find out network details of host.
  • JDK class InetAddress provide APIs to fetch network details of hosts.
  • We will retrieve network details for:
    • Loopback address or localhost
    • Get network details for public hosts like facebook or youtube.
    • Also, get network details of host if it is mapped to multiple IP addresses.

Get Network details like IPAddress, hostname for loopback:

Example 1: Input loopback hostname i.e. localhost
We will use API InetAddress.getLoopbackAddress() to get loopback details.
 
Output: We would get network details like IP Address, hostname as follows
Ip Address:127.0.0.1, Host Name: localhost, Canonical Name: 127.0.0.1
 
Example 2: Get network details for localhost
We will use InetAddress.getLocalHost() to get details like IP address, canonical name.
 
Output for localhost is: Ip Address:192.168.43.201, Host Name: 5AYX2L07

Get network details for public hosts like facebook or youtube:

Example 3:
 
Get network details for public hosts like facebook or youtube.
We will use API InetAddress.getByName("www.facebook.com") to fetch network details.
 
Output: currently, we are getting following details (it may vary)
Ip Address:157.240.7.35, Host Name: www.facebook.com,
Canonical Name: edge-star-mini-shv-01-sin6.facebook.com
 
Example 4:
Get all network addresses if hostname is mapped to multiple IP address.
 
Retrieve all network Address of hostname using API InetAddress.getAllByName("www.fb.com")
 
Output: we are getting output as follows:
Ip Address:31.13.78.35, Host Name: www.fb.com

Network details for hosts (loopback, local & standard hosts) in java

package org.learn.nw;
 
import java.net.InetAddress;
import java.net.UnknownHostException;
 
public class HostNameIpAddress {
    public static void main(String[] args) throws UnknownHostException {
 
        //Loop back address and hostname
        InetAddress inetAddress = InetAddress.getLoopbackAddress();
        System.out.println("1. Loop back ip address and hostname");
        display(inetAddress);
 
        //Local ip address and hostname
        System.out.println("\n2. Local ip address and hostname");
        inetAddress = InetAddress.getLocalHost();
        display(inetAddress);
 
        //Get IP address of given hostname
        System.out.println("\n3. Standard host ip address from hostname");
        inetAddress = InetAddress.getByName("www.facebook.com");
        display(inetAddress);
 
        //Get list of IP address for given hostname.
        System.out.println("\n4. All IP address corresponding to given hostname");
        InetAddress[] allInetAddress = InetAddress.getAllByName("www.fb.com");
        for(InetAddress netAddress : allInetAddress) {
            display(netAddress);
            System.out.println();
        }
    }
 
    private static void display(InetAddress inetAddress) {
        System.out.printf("Ip Address:%s, Host Name: %s, Canonical Name: %s",
                    inetAddress.getHostAddress(), inetAddress.getHostName(),
                    inetAddress.getCanonicalHostName());
    }
}

Output: Network details for hosts in java (example)

1. Loop back ip address and hostname
Ip Address:127.0.0.1, Host Name: localhost, Canonical Name: 127.0.0.1
2. Local ip address and hostname
Ip Address:192.168.43.201, Host Name: 5AYX2L07, Canonical Name: 2YR1L72.xyz.com
3. Standard host ip address from hostname
Ip Address:157.240.7.35, Host Name: www.facebook.com, Canonical Name: edge-star-mini-shv-01-sin6.facebook.com
4. All IP address corresponding to given hostname
Ip Address:31.13.78.35, Host Name: www.fb.com, Canonical Name: edge-star-mini-shv-01-sit4.facebook.com

No related posts.