Response time out when pinging an IP address in Java

Question

Here is what I use to ping an IPv4-Address and to record the actual response time in ms. Unfortunately I never get a valid response.. The request always times out. 0 is always returned. Please help :)

private long pingHost(String host, int port) {
    try {                   
        Inet4Address inet4 = (Inet4Address)InetAddress.getByName(host);         
        long start = System.currentTimeMillis();
        if(inet4.isReachable(5000)){
            long end = System.currentTimeMillis();
            long total = end-start;
            System.out.println(total);
            return total;
        }   

    } catch (UnknownHostException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return 0;

}

Try a ping in the shell of your operating system. A firewall on the remote host might block that ping. — Tom, Jan 09 '15 at 22:12
possible duplicate of [Why does InetAddress.isReachable return false, when I can ping the IP address?](http://stackoverflow.com/questions/9922543/why-does-inetaddress-isreachable-return-false-when-i-can-ping-the-ip-address) — Todd, Jan 09 '15 at 22:17
Neither of these has helped me. I ping an IP address not an URL. — chrisyou, Jan 09 '15 at 22:26

score 0 · Answer 1 · edited May 23 '17 at 12:11

0

Create a process in Java and execute the ping command in it. The isReachable method is known to not work.

See this answer for more details and code examples.

edited May 23 '17 at 12:11

Community

1
1

answered Jan 09 '15 at 22:17

nhylated

1,575
13
19

score 0 · Answer 2 · answered Jan 09 '15 at 22:26

0

Have you tried with

isReachable(NetworkInterface netif, int ttl, int timeout) Test whether that address is reachable.

Your time to live might be to small so the connection never reaches the destination.

answered Jan 09 '15 at 22:26

Daniel Persson

602
7
17

Even with 25 hops it does not become true. – chrisyou Jan 09 '15 at 22:31

score 0 · Answer 3 · answered Oct 17 '21 at 12:37

May be use Socket? Something like this:

class PingTask implements Runnable {

    private int timeout;
    private Target target;// has InetSocketAddress field (getAddress()...)

    PingTask(Target target, int timeout) {
            this.target = target;
            this.timeout = timeout;
    }

    public String getHost() {
            return target.getAddress().getAddress() + ":" + target.getAddress().getPort();
    }

    @Override
    public void run() {
            Socket connection = new Socket();
            boolean reachable;
            long start = System.currentTimeMillis();
            try {
                    try {
                            connection.connect(target.getAddress(), timeout);
                    } finally {
                            connection.close();
                    }
                    long dur = (System.currentTimeMillis() - start);
                    System.out.printf("%5d ms %s%n", dur, target.getAddress().getHostString() );
                    reachable = true;
            } catch (Exception e) {
                    reachable = false;
            }

            if (!reachable) {
                    System.out.println(
                            String.format(
                                    "\t%s was UNREACHABLE",
                                    getHost()
                            )
                    );
            }
    } }

Response time out when pinging an IP address in Java

3 Answers3