Re: Echo packet

From:
RedGrittyBrick <RedGrittyBrick@SpamWeary.foo>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 11 Apr 2008 11:44:14 +0100
Message-ID:
<47ff40fe$0$26079$db0fefd9@news.zen.co.uk>
BigZero originally wrote:

hello,
i need to send echo packet as broadcast and store the responded ip
address ,i need to use UDP packet that is datagram Packet so any one
can help how to code this one


BigZero later wrote:

Well i do not known where to post so i m posting here only, let this
can help u to under stand.
here is my code i m using snmp4j pack,


<snip program using SNMP4J>

hope now it may clear u


That is much clearer. In your original posting (in *this* thread) you
mentioned UDP Datagrams, you said nothing about SNMP. A better subject
line might have been "Problems with SNMP using SNMP4J".

I can't help you with SNMP, particularly as there are many different
SNMP stacks.

What follows is of no use to the OP (BigZero) - but here is a simple
example in case any other google/newsreader-user read this thread
because the OP mentioned "Echo packet" "Broadcast" "UDP" "datagram":

------------------------------ 8< ------------------------------------
public class UdpPing {
     // NOTE: needs extending to capture *all* reponders.

     static final String BROADCAST = "255.255.255.255";

     static final int ECHOPORT = 7;

     public static void main(String[] args) {

         try {
             DatagramSocket socket = new DatagramSocket();
             socket.setSoTimeout(1000); // in mSec.

             // send request
             byte[] buf = new byte[256];
             InetAddress address;
             address = InetAddress.getByName(BROADCAST);
             DatagramPacket packet = new DatagramPacket(buf, buf.length,
                     address, ECHOPORT);
             socket.send(packet);

             // get response
             packet = new DatagramPacket(buf, buf.length);
             socket.receive(packet);

             // see who responded first
             InetAddress responder = packet.getAddress();
             System.out.println(responder + " responded.");

             socket.close();

         } catch (Exception e) {
             e.printStackTrace();
         }

     }
}
------------------------------ 8< ------------------------------------

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