Java InetAddress.getByName returns hostname/ip but it causes ping to fail

Question

I am using correto java 11 JDK

Here is my method:

public static boolean sendPingRequest(String host)
{
    boolean value = false;

    try
    {
        InetAddress myip = InetAddress.getByName(host);
        System.out.println("Sending Ping Request to " + myip);

        if (myip.isReachable(5000))
        {

            System.out.println("Host: " + host + " is reachable");
            value = true;
        }
        else
        {

            System.out.println("Host: " + host + " is unreachable");
        }
    }
    catch (UnknownHostException e)
    {

        System.out.println("I can't reach this host: " + e.getMessage());
        e.printStackTrace();
    }
    catch (IOException e)
    {
        System.out.println("IO Exception" + e.getMessage());
    }
    return value;
}

When I can the method here it fails

String myHost = "www.google.com";
sendPingRequest(myHost);

Sending Ping Request to www.google.com/108.177.111.106 Host: www.google.com is unreachable Process finished with exit code 0

From reading the documentation it looks like InetAddress.getByName method returns this but it will fail every time unless I can get it to show the host to be the IP 108.177.111.106.

Answer 1

I can't reproduce your issue. Here's what I tried:

public class Main {

    public static void main(String[] args) {
        System.out.println(sendPingRequest("www.google.com"));
        System.out.println(sendPingRequest("74.125.195.106"));
        System.out.println(sendPingRequest("108.177.111.106"));
    }

    public static boolean sendPingRequest(String host) {
        boolean value = false;

        try {
            InetAddress myip = InetAddress.getByName(host);
            System.out.println("Sending Ping Request to " + myip);
            if (myip.isReachable(5000)) {
                System.out.println("Host: " + host + " is reachable");
                value = true;
            } else {
                System.out.println("Host: " + host + " is unreachable");
            }
        } catch (UnknownHostException e) {
            System.out.println("I can't reach this host: " + e.getMessage());
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("IO Exception" + e.getMessage());
        }
        return value;
    }
}

and the output is

Sending Ping Request to www.google.com/74.125.195.105
Host: www.google.com is reachable
true
Sending Ping Request to /74.125.195.106
Host: 74.125.195.106 is reachable
true
Sending Ping Request to /108.177.111.106
Host: 108.177.111.106 is reachable
true

Perhaps you were having network issues?