InetAddress.isReachable returns true when pointing a host ip that actually does not exist.

OS: RHEL4 or RHEL AS 3.
JDK: jdk 6u2, jdk 5u2

Below is the test program. To reproduce you must run the TP with root authority.

---->
import java.net.*;

class Multiping extends Thread {
    private InetAddress addr;
    private boolean reachable;
    static volatile boolean finish;

    public static void main( String arg[] ) throws Exception{
        new Multiping("192.168.3.2", true).start(); // put reachable host ip here
        new Multiping("10.210.45.39", false).start(); // put unreachable host ip
        finish = false;

        Thread.sleep(20000);
        finish = true;
    }

    Multiping( String str, boolean f ) {
        reachable = f;
        try {
            addr = InetAddress.getByName( str );
        }
        catch ( UnknownHostException e ) {
            e.printStackTrace();
            System.exit(1);
        }
    }

    public void run() {
        try {
            while( finish == false ) {
                boolean result = addr.isReachable(3000);
                if ( result != reachable ) {
                    if ( result ) {
                        System.out.println(addr+":reachable ... unexpected result");
                        System.exit(1);
                    }
                    else {
                        System.out.println(addr+":unreachable ... unexpected result");
                        System.exit(1);
                    }
                }
            }
        }
        catch(Exception e){
            e.printStackTrace();
        }
    }
}
<----

The following is the TP's result I ran.

[root@kronos isReachable]# /home/xz137640/jdk/6u2/bin/java Multiping
/10.210.45.39:reachable ... unexpected result

It seems that the implementation can not determine the response is from which host because of raw packet using.