Question

InetAddress address = InetAddress.getByAddress( new byte[] { (byte) 192, (byte) 168, (byte) 254, (byte) 10 ); success = address.isReachable( 3000 );

This returns false even though I am reasonably sure it is a reachable address.

I found that if I changed this to 127, 0, 0, 1 it returned success.

My next attempt was same code, but I used the address I got from a ping of http://www.google.com ( 72.167.164.64 as of this writing ). No success.

Answer 1

You can create a servlet/webpages or whatever you feel comfortable on the server that return ok or error depending on server status from your android you must call that url and check returned value, also on your try/catch you must watch specific exception for example related with timeout, also check for http status if your http request returned 200 then was ok and you can fetch server status from that url

Check http://developer.android.com/reference/java/net/HttpURLConnection.html

boolean isOK = false;
try {
    URL url = new URL("http://yourserverurl/yourstatusmethod");
    HttpURLConnection urlcon = (HttpURLConnection) url.openConnection();
    urlcon.connect();
    if (urlcon.getResponseCode() == 200) {
            InputStream in = new BufferedInputStream(urlConnection.getInputStream());
            String serverStatus = readStream(in); //assuming that "http://yourserverurl/yourstatusmethod" returns OK or ERROR depending on your server status check         
            isOK = (serverStatus.equalsIgnoreCase("OK"));
    }else{
      isOK = false;
    }

    url.disconnect();

} catch (MalformedURLException e1) {
            isOK = false;
            e1.printStackTrace();
} catch (IOException e) {
            isOK = false;
            e.printStackTrace();
}

the readStream is a method that convert inputstream to string

public static String readStream (InputStream in) throws IOException {
    StringBuffer out = new StringBuffer();
    byte[] b = new byte[4096];
    for (int n; (n = in.read(b)) != -1;) {
        out.append(new String(b, 0, n));
    }
    return out.toString();
}

this is just and idea…. there are a lot of ways to check server availability