Broadcast a UDP packet

Hi,
I am using flex builder 3.5. I made a Datagram socket and want to broadcast the packet. But when I tried to send packet at 255.255.255.255(Broadcast address), I got the invalid socket error. How Can I do this??
Thanks

Similar Messages

Broadcast large UDP datagrams between VLANs

Hello,
I wish to broadcast large UDP packets between two VLANs (on the one set of stacked 3750 switches).
I have setup an ip helper which allows me to broadcast between vlans. That works fine, but I am limited to datagrams around 5912 bytes in size.
I want to be able to broadcast larger datagrams.
I can successfully broadcast larger datagrams (65000-ish bytes) within the one vlan, but not between two vlans.
Am I able to increase the size of broadcast UDP datagrams between vlans and if so, how?
Thanks in advance.

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Posting
Hmm, I'm wondering whether a helper cannot forward fragments.
If not, if you enable jumbo support on the 3750, you might be able to send larger diagrams, but perhaps not larger than MTU.

Broadcasting/multicasting UDP

Is it possible to broadcast UDP packets directly from the host machine's IP address on a selected port so that anyone listening on that IP address/port can receive them? If not, how should a server go about finding an appropriate IP address/port within the 224.0.0.0 - 239.255.255.255 range to send packets on?

Dear Josh,
You send the UDP paket to a multicast (class D) IP address/port and the rest is the duty of the multicasting server.
The mechnism of multicasting and how could Java programmer make use of it is some thing missed in the documents availabe. I've searched for that but all I got is an RMS "Reliable Multicast Service" Libraries like:
JRMS at www.experimentalstuff.com
JGroups at www.JGroups.org
But these are libraries and focusing on the reliable multicast. If we need to multicast an audio stream we need only basic multicast using "MulticastSoket" from java.net package.
But again the system is no only a set of API's. The question is HOW to build a multicasting audio service using java and whta do we need with java??
the answer could be of great help
Ahmad Khalafallah
[email protected]

IP Multicast: UDP Packet size!

Hi,
          Does anyone know what is the size of the UDP packets which WLS
          allocates to receive broadcast messages in a clsutered enviroment. I am
          running into issues as we have a limitation on JVM/platform combination,
          where we can have message size of only 32K be allocated for UDP packets
          ?? Is ther eany way to configure WLS to use smaller packet sizes?
          TIA,
          Sam


WLS uses 32 K. UDP packets by default. So, you should not have any problems
          on our certified platforms.
          Are you by any chance trying to run the server on Tandem?
          Thanks,
          Michael
          Michael Girdley
          WLS Product Manager
          Sam <[email protected]> wrote in message
          news:[email protected]..
          > Hi,
          >
          > Does anyone know what is the size of the UDP packets which WLS
          > allocates to receive broadcast messages in a clsutered enviroment. I am
          > running into issues as we have a limitation on JVM/platform combination,
          > where we can have message size of only 32K be allocated for UDP packets
          > ?? Is ther eany way to configure WLS to use smaller packet sizes?
          >
          > TIA,
          >
          > Sam
          >

JMF How to stream rtp from udp packet

I implemented an rtsp client and use the client to setup two rtp session(audio, vedio). But when I use the example pramgram "AVReceive3" to stream the udp packet, it doesn't work.
When the AVReceive3 receive the udp packet from the rtp port, it will call the update(ReceiveStreamEvent evt) function, and the event type is StreamMappedEvent, and the call to evt.getReceiveStream().getDataSource() return null.
I thought the first event should be NewReceiveStreamEvent. Please help to solve the problem.
What's rtp packet will cause the event StreamMappedEvent.
Following is the code of AVReceive3.java:
* AVReceive3.java
* Created on 2007年10月30日, 下午4:11
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
package PlayerTest;
import java.io.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
import java.util.Vector;
import javax.media.*;
import javax.media.rtp.*;
import javax.media.rtp.event.*;
import javax.media.rtp.rtcp.*;
import javax.media.protocol.*;
import javax.media.protocol.DataSource;
import javax.media.format.AudioFormat;
import javax.media.format.VideoFormat;
import javax.media.Format;
import javax.media.format.FormatChangeEvent;
import javax.media.control.BufferControl;
* AVReceive3 to receive RTP transmission using the RTPConnector.
public class AVReceive3 extends Thread implements ReceiveStreamListener, SessionListener,
ControllerListener
String sessions[] = null;
RTPManager mgrs[] = null;
Vector playerWindows = null;
boolean dataReceived = false;
Object dataSync = new Object();
public AVReceive3(String sessions[])
this.sessions = sessions;
public void run()
initialize();
public boolean initialize() {
try {
mgrs = new RTPManager[sessions.length];
playerWindows = new Vector();
SessionLabel session;
// Open the RTP sessions.
for (int i = 0; i < sessions.length; i++) {
// Parse the session addresses.
try {
session = new SessionLabel(sessions);
} catch (IllegalArgumentException e) {
System.err.println("Failed to parse the session address given: " + sessions[i]);
return false;
System.err.println(" - Open RTP session for: addr: " + session.addr + " port: " + session.port + " ttl: " + session.ttl);
mgrs[i] = (RTPManager) RTPManager.newInstance();
mgrs[i].addSessionListener(this);
mgrs[i].addReceiveStreamListener(this);
// Initialize the RTPManager with the RTPSocketAdapter
mgrs[i].initialize(new RTPSocketAdapter(
InetAddress.getByName(session.addr),
session.port, session.ttl));
// You can try out some other buffer size to see
// if you can get better smoothness.
BufferControl bc = (BufferControl)mgrs[i].getControl("javax.media.control.BufferControl");
if (bc != null)
bc.setBufferLength(350);
} catch (Exception e){
System.err.println("Cannot create the RTP Session: " + e.getMessage());
return false;
// Wait for data to arrive before moving on.
long then = System.currentTimeMillis();
long waitingPeriod = 30000; // wait for a maximum of 30 secs.
try{
synchronized (dataSync) {
while (!dataReceived &&
System.currentTimeMillis() - then < waitingPeriod) {
if (!dataReceived)
System.err.println(" - Waiting for RTP data to arrive");
dataSync.wait(1000);
} catch (Exception e) {}
if (!dataReceived) {
System.err.println("No RTP data was received.");
close();
return false;
return true;
public boolean isDone() {
return playerWindows.size() == 0;
* Close the players and the session managers.
protected void close() {
for (int i = 0; i < playerWindows.size(); i++) {
try {
((PlayerWindow)playerWindows.elementAt(i)).close();
} catch (Exception e) {}
playerWindows.removeAllElements();
// close the RTP session.
for (int i = 0; i < mgrs.length; i++) {
if (mgrs[i] != null) {
mgrs[i].removeTargets( "Closing session from AVReceive3");
mgrs[i].dispose();
mgrs[i] = null;
PlayerWindow find(Player p) {
for (int i = 0; i < playerWindows.size(); i++) {
PlayerWindow pw = (PlayerWindow)playerWindows.elementAt(i);
if (pw.player == p)
return pw;
return null;
PlayerWindow find(ReceiveStream strm) {
for (int i = 0; i < playerWindows.size(); i++) {
PlayerWindow pw = (PlayerWindow)playerWindows.elementAt(i);
if (pw.stream == strm)
return pw;
return null;
* SessionListener.
public synchronized void update(SessionEvent evt) {
if (evt instanceof NewParticipantEvent) {
Participant p = ((NewParticipantEvent)evt).getParticipant();
System.err.println(" - A new participant had just joined: " + p.getCNAME());
* ReceiveStreamListener
public synchronized void update( ReceiveStreamEvent evt) {
System.out.println("\nReceive an receiveStreamEvent:"+evt.toString());
RTPManager mgr = (RTPManager)evt.getSource();
Participant participant = evt.getParticipant(); // could be null.
ReceiveStream stream = evt.getReceiveStream(); // could be null.
System.out.println("The RTPManager is:");
if (evt instanceof RemotePayloadChangeEvent) {
System.err.println(" - Received an RTP PayloadChangeEvent.");
System.err.println("Sorry, cannot handle payload change.");
System.exit(0);
else if (evt instanceof NewReceiveStreamEvent) {
try {
stream = ((NewReceiveStreamEvent)evt).getReceiveStream();
DataSource ds = stream.getDataSource();
// Find out the formats.
RTPControl ctl = (RTPControl)ds.getControl("javax.media.rtp.RTPControl");
if (ctl != null){
System.err.println(" - Recevied new RTP stream: " + ctl.getFormat());
} else
System.err.println(" - Recevied new RTP stream");
if (participant == null)
System.err.println(" The sender of this stream had yet to be identified.");
else {
System.err.println(" The stream comes from: " + participant.getCNAME());
// create a player by passing datasource to the Media Manager
Player p = javax.media.Manager.createPlayer(ds);
if (p == null)
return;
p.addControllerListener(this);
p.realize();
PlayerWindow pw = new PlayerWindow(p, stream);
playerWindows.addElement(pw);
pw.setVisible(true);
// Notify intialize() that a new stream had arrived.
synchronized (dataSync) {
dataReceived = true;
dataSync.notifyAll();
} catch (Exception e) {
System.err.println("NewReceiveStreamEvent exception " + e.getMessage());
return;
else if (evt instanceof StreamMappedEvent) {
if (stream != null)
if(stream.getDataSource()!=null)
DataSource ds = stream.getDataSource();
// Find out the formats.
RTPControl ctl = (RTPControl)ds.getControl("javax.media.rtp.RTPControl");
System.err.println(" - The previously unidentified stream ");
if (ctl != null)
System.err.println(" " + ctl.getFormat());
System.err.println(" had now been identified as sent by: " + participant.getCNAME());
else if (evt instanceof ByeEvent) {
System.err.println(" - Got \"bye\" from: " + participant.getCNAME());
PlayerWindow pw = find(stream);
if (pw != null) {
pw.close();
playerWindows.removeElement(pw);
* ControllerListener for the Players.
public synchronized void controllerUpdate(ControllerEvent ce) {
Player p = (Player)ce.getSourceController();
if (p == null)
return;
// Get this when the internal players are realized.
if (ce instanceof RealizeCompleteEvent) {
PlayerWindow pw = find(p);
if (pw == null) {
// Some strange happened.
System.err.println("Internal error!");
System.exit(-1);
pw.initialize();
pw.setVisible(true);
p.start();
if (ce instanceof ControllerErrorEvent) {
p.removeControllerListener(this);
PlayerWindow pw = find(p);
if (pw != null) {
pw.close();
playerWindows.removeElement(pw);
System.err.println("AVReceive3 internal error: " + ce);
* A utility class to parse the session addresses.
class SessionLabel {
public String addr = null;
public int port;
public int ttl = 1;
SessionLabel(String session) throws IllegalArgumentException {
int off;
String portStr = null, ttlStr = null;
if (session != null && session.length() > 0) {
while (session.length() > 1 && session.charAt(0) == '/')
session = session.substring(1);
// Now see if there's a addr specified.
off = session.indexOf('/');
if (off == -1) {
if (!session.equals(""))
addr = session;
} else {
addr = session.substring(0, off);
session = session.substring(off + 1);
// Now see if there's a port specified
off = session.indexOf('/');
if (off == -1) {
if (!session.equals(""))
portStr = session;
} else {
portStr = session.substring(0, off);
session = session.substring(off + 1);
// Now see if there's a ttl specified
off = session.indexOf('/');
if (off == -1) {
if (!session.equals(""))
ttlStr = session;
} else {
ttlStr = session.substring(0, off);
if (addr == null)
throw new IllegalArgumentException();
if (portStr != null) {
try {
Integer integer = Integer.valueOf(portStr);
if (integer != null)
port = integer.intValue();
} catch (Throwable t) {
throw new IllegalArgumentException();
} else
throw new IllegalArgumentException();
if (ttlStr != null) {
try {
Integer integer = Integer.valueOf(ttlStr);
if (integer != null)
ttl = integer.intValue();
} catch (Throwable t) {
throw new IllegalArgumentException();
* GUI classes for the Player.
class PlayerWindow extends Frame {
Player player;
ReceiveStream stream;
PlayerWindow(Player p, ReceiveStream strm) {
player = p;
stream = strm;
public void initialize() {
add(new PlayerPanel(player));
public void close() {
player.close();
setVisible(false);
dispose();
public void addNotify() {
super.addNotify();
pack();
* GUI classes for the Player.
class PlayerPanel extends Panel {
Component vc, cc;
PlayerPanel(Player p) {
setLayout(new BorderLayout());
if ((vc = p.getVisualComponent()) != null)
add("Center", vc);
if ((cc = p.getControlPanelComponent()) != null)
add("South", cc);
public Dimension getPreferredSize() {
int w = 0, h = 0;
if (vc != null) {
Dimension size = vc.getPreferredSize();
w = size.width;
h = size.height;
if (cc != null) {
Dimension size = cc.getPreferredSize();
if (w == 0)
w = size.width;
h += size.height;
if (w < 160)
w = 160;
return new Dimension(w, h);
public static void main(String argv[]) {
//if (argv.length == 0)
// prUsage();
String sessions[]= new String[] {"127.0.0.1/6670","127.0.0.1/6672"};
AVReceive3 avReceive = new AVReceive3(sessions);
if (!avReceive.initialize()) {
System.err.println("Failed to initialize the sessions.");
System.exit(-1);
// Check to see if AVReceive3 is done.
try {
while (!avReceive.isDone())
Thread.sleep(1000);
} catch (Exception e) {}
System.err.println("Exiting AVReceive3");
static void prUsage() {
System.err.println("Usage: AVReceive3 <session> <session> ");
System.err.println(" <session>: <address>/<port>/<ttl>");
System.exit(0);
}// end of AVReceive3
Following is the code of RTPSocketAdapter.java:
* RTPSocketAdapter.java
* Created on 2007年10月30日, 下午4:13
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
package PlayerTest;
import java.io.IOException;
import java.net.InetAddress;
import java.net.DatagramSocket;
import java.net.MulticastSocket;
import java.net.DatagramPacket;
import java.net.SocketException;
import javax.media.protocol.DataSource;
import javax.media.protocol.PushSourceStream;
import javax.media.protocol.ContentDescriptor;
import javax.media.protocol.SourceTransferHandler;
import javax.media.rtp.RTPConnector;
import javax.media.rtp.OutputDataStream;
* An implementation of RTPConnector based on UDP sockets.
public class RTPSocketAdapter implements RTPConnector {
DatagramSocket dataSock;
DatagramSocket ctrlSock;
InetAddress addr;
int port;
SockInputStream dataInStrm = null;
SockInputStream ctrlInStrm = null;
SockOutputStream dataOutStrm = null;
SockOutputStream ctrlOutStrm = null;
public RTPSocketAdapter(InetAddress addr, int port) throws IOException {
this(addr, port, 1);
public RTPSocketAdapter(InetAddress addr, int port, int ttl) throws IOException {
try {
if (addr.isMulticastAddress()) {
dataSock = new MulticastSocket(port);
ctrlSock = new MulticastSocket(port+1);
((MulticastSocket)dataSock).joinGroup(addr);
((MulticastSocket)dataSock).setTimeToLive(ttl);
((MulticastSocket)ctrlSock).joinGroup(addr);
((MulticastSocket)ctrlSock).setTimeToLive(ttl);
} else {
dataSock = new DatagramSocket(port, InetAddress.getLocalHost());
ctrlSock = new DatagramSocket(port+1, InetAddress.getLocalHost());
} catch (SocketException e) {
throw new IOException(e.getMessage());
this.addr = addr;
this.port = port;
* Returns an input stream to receive the RTP data.
public PushSourceStream getDataInputStream() throws IOException {
if (dataInStrm == null) {
dataInStrm = new SockInputStream(dataSock, addr, port);
dataInStrm.start();
return dataInStrm;
* Returns an output stream to send the RTP data.
public OutputDataStream getDataOutputStream() throws IOException {
if (dataOutStrm == null)
dataOutStrm = new SockOutputStream(dataSock, addr, port);
return dataOutStrm;
* Returns an input stream to receive the RTCP data.
public PushSourceStream getControlInputStream() throws IOException {
if (ctrlInStrm == null) {
ctrlInStrm = new SockInputStream(ctrlSock, addr, port+1);
ctrlInStrm.start();
return ctrlInStrm;
* Returns an output stream to send the RTCP data.
public OutputDataStream getControlOutputStream() throws IOException {
if (ctrlOutStrm == null)
ctrlOutStrm = new SockOutputStream(ctrlSock, addr, port+1);
return ctrlOutStrm;
* Close all the RTP, RTCP streams.
public void close() {
if (dataInStrm != null)
dataInStrm.kill();
if (ctrlInStrm != null)
ctrlInStrm.kill();
dataSock.close();
ctrlSock.close();
* Set the receive buffer size of the RTP data channel.
* This is only a hint to the implementation. The actual implementation
* may not be able to do anything to this.
public void setReceiveBufferSize( int size) throws IOException {
dataSock.setReceiveBufferSize(size);
* Get the receive buffer size set on the RTP data channel.
* Return -1 if the receive buffer size is not applicable for
* the implementation.
public int getReceiveBufferSize() {
try {
return dataSock.getReceiveBufferSize();
} catch (Exception e) {
return -1;
* Set the send buffer size of the RTP data channel.
* This is only a hint to the implementation. The actual implementation
* may not be able to do anything to this.
public void setSendBufferSize( int size) throws IOException {
dataSock.setSendBufferSize(size);
* Get the send buffer size set on the RTP data channel.
* Return -1 if the send buffer size is not applicable for
* the implementation.
public int getSendBufferSize() {
try {
return dataSock.getSendBufferSize();
} catch (Exception e) {
return -1;
* Return the RTCP bandwidth fraction. This value is used to
* initialize the RTPManager. Check RTPManager for more detauls.
* Return -1 to use the default values.
public double getRTCPBandwidthFraction() {
return -1;
* Return the RTCP sender bandwidth fraction. This value is used to
* initialize the RTPManager. Check RTPManager for more detauls.
* Return -1 to use the default values.
public double getRTCPSenderBandwidthFraction() {
return -1;
* An inner class to implement an OutputDataStream based on UDP sockets.
class SockOutputStream implements OutputDataStream {
DatagramSocket sock;
InetAddress addr;
int port;
public SockOutputStream(DatagramSocket sock, InetAddress addr, int port) {
this.sock = sock;
this.addr = addr;
this.port = port;
public int write(byte data[], int offset, int len) {
try {
sock.send(new DatagramPacket(data, offset, len, addr, port));
} catch (Exception e) {
return -1;
return len;
* An inner class to implement an PushSourceStream based on UDP sockets.
class SockInputStream extends Thread implements PushSourceStream {
DatagramSocket sock;
InetAddress addr;
int port;
boolean done = false;
boolean dataRead = false;
SourceTransferHandler sth = null;
public SockInputStream(DatagramSocket sock, InetAddress addr, int port) {
this.sock = sock;
this.addr = addr;
this.port = port;
public int read(byte buffer[], int offset, int length) {
DatagramPacket p = new DatagramPacket(buffer, offset, length, addr, port);
try {
sock.receive(p);
} catch (IOException e) {
return -1;
synchronized (this) {
dataRead = true;
notify();
System.out.println("RTPSocketAdapter receive RTP packet from port:"+port);
System.out.println("The received RTP packet:"+new String(buffer));
return p.getLength();
public synchronized void start() {
super.start();
if (sth != null) {
dataRead = true;
notify();
public synchronized void kill() {
done = true;
notify();
public int getMinimumTransferSize() {
return 2 * 1024; // twice the MTU size, just to be safe.
public synchronized void setTransferHandler(SourceTransferHandler sth) {
this.sth = sth;
dataRead = true;
notify();
// Not applicable.
public ContentDescriptor getContentDescriptor() {
return null;
// Not applicable.
public long getContentLength() {
return LENGTH_UNKNOWN;
// Not applicable.
public boolean endOfStream() {
return false;
// Not applicable.
public Object[] getControls() {
return new Object[0];
// Not applicable.
public Object getControl(String type) {
return null;
* Loop and notify the transfer handler of new data.
public void run() {
while (!done) {
synchronized (this) {
while (!dataRead && !done) {
try {
wait();
} catch (InterruptedException e) { }
dataRead = false;
if (sth != null && !done) {
sth.transferData(this);
Thanks.

The error of No format has been registered for RTP Payload type 96
is caused by the dynamic payload mapping, when I add the dynamic mapping between dynamic payload and format. The Player cann't work yet. I think it because JMF doesn't support the format of my clips. For example:
video: a=rtpmap:96 H263-2000/90000
audio:a=rtpmap:97 MP4A-LATM/12000/1
Is there some available plugin to support these format?
Thanks

DNS after reducing the advertised EDNS UDP packet size to 512 octets

hello
There is something wrong with my DNS server, it open internet webs so slow,and i have no idea with this .
04-Mar-2011 14:31:57.264 zone 0.0.127.in-addr.arpa/IN/com.apple.ServerAdmin.DNS.public: loaded serial 1997022700
04-Mar-2011 14:31:57.264 zone 15.0.168.192.in-addr.arpa/IN/com.apple.ServerAdmin.DNS.public: loaded serial 2011030204
04-Mar-2011 14:31:57.265 zone ******/IN/com.apple.ServerAdmin.DNS.public: loaded serial 2011030404
04-Mar-2011 14:31:57.265 zone localhost/IN/com.apple.ServerAdmin.DNS.public: loaded serial 42
04-Mar-2011 14:31:57.265 running
04-Mar-2011 14:32:00.066 host unreachable resolving 'b.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:7fd::1#53
04-Mar-2011 14:32:00.261 host unreachable resolving 'r.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:500:2f::f#53
04-Mar-2011 14:32:00.261 host unreachable resolving 'r.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:503:c27::2:30#53
04-Mar-2011 14:32:00.261 host unreachable resolving 'r.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:503:ba3e::2:30#53
04-Mar-2011 14:32:00.261 host unreachable resolving 'r.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:7fd::1#53
04-Mar-2011 14:32:00.261 host unreachable resolving 'r.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:dc3::35#53
04-Mar-2011 14:32:00.361 host unreachable resolving 'dr.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:500:1::803f:235#53
04-Mar-2011 14:32:00.361 host unreachable resolving 'dr.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:7fd::1#53
04-Mar-2011 14:32:00.361 host unreachable resolving 'dr.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:dc3::35#53
04-Mar-2011 14:32:00.361 host unreachable resolving 'dr.dns-sd.udp.0.0.168.192.in-addr.arpa/PTR/IN': 2001:503:ba3e::2:30#53
04-Mar-2011 14:32:00.866 host unreachable resolving './NS/IN': 2001:7fd::1#53
04-Mar-2011 14:32:01.005 success resolving './NS' (in '.'?) after reducing the advertised EDNS UDP packet size to 512 octets
04-Mar-2011 14:32:01.408 success resolving 'local/SOA' (in '.'?) after disabling EDNS
04-Mar-2011 14:32:01.533 host unreachable resolving 't.arin.net/AAAA/IN': 2001:503:ba3e::2:30#53
04-Mar-2011 14:32:01.534 host unreachable resolving 'v.arin.net/AAAA/IN': 2001:500:1::803f:235#53
04-Mar-2011 14:32:01.534 host unreachable resolving 'v.arin.net/AAAA/IN': 2001:7fd::1#53
04-Mar-2011 14:32:01.534 host unreachable resolving 'v.arin.net/AAAA/IN': 2001:503:ba3e::2:30#53
04-Mar-2011 14:32:01.534 host unreachable resolving 'w.arin.net/A/IN': 2001:500:1::803f:235#53
anyone help!! Thanks a lot.
Message was edited by: leo.xue

also interesting, when setting DNS servers IPs in Network Settings for your host,
it is important that the IPs are not doubled.
in example if you have Networksettings like
automatic DHCP given from router or server.
IP-Adress: 192.168.2.2
Subnetmask: 255.255.255.0
Router IP: 192.168.2.1
DNS-Server: 127.0.0.1, 192.168.2.2
wich means localhost and again same machine, just different IP..
then your lookup mechanism has to walk thru this steps to know if there is nothing inside to resolve adresses.
which means in this example it would take double the time if DNS-Server would be just 127.0.0.1
you can see if there is a lot to work thru in your logs.
look for something like "sizing zone task pool based on 9 zones".
this mount of zones will change if you set the correct DNS server IP.
more zones are slower than less, very logical!
but this will not solve your problem with packet size at all, it just reduces circles after dns resolves not known adresses even with packet size change.

ASA 5510 'bounces' UDP packets. Why?

Hi. I hope to find someone who can shed a light on something that is bugging me for days now. We have an ASA (5510, running 7.2(2)) to connect our subnets to the backbone of the ISP. I received complaints about one specific connection, which I'll "draw" here:
[ remote host 192.87.x.y (A) ] -- {"Internet"} -- [ Telecity Router ] -- [ Our ASA ] -- [ switch ] -- [ fibre ] -- [ switch ] -- [ our host 82.199.c.d (B) ]
What happens is the following: I can successfully ping from A to B and back. I can also traceroute (UDP) from A to B and back. But a specific UDP packet sent by A (port 9001) to B (port 5432) is causing a problem. "Our ASA" does not route the packet to the correct interface, but sends it back to the Telecity router instead. Which in turn sends it back to "Our ASA" (since it is destined for our subnet). This goes back and forth for 60 times and then the TTL is expired.
I have no idear what is happening here. The access-lists are correctly configured (as far as I know), but even if they weren't I would expect the packets to get dropped rather than put back on the sending interface. This packet is bounced (on ethernetlevel, the IP part remains the same apart from the TTL) to the sending router.
Any pointers as to where to look for what is causing this and how to investigate this further are highly appreciated.
Frank

Hi Frederico. Of course I tried the packet tracer as one of the first tools :-). It showed a complete path (I used ASDM). Now I retried it (via the CLI) and something strange happens. This is a packet trace A to B with udp from port 9001 to 5431 (not 5432):
Phase: 1
Type: FLOW-LOOKUP / ALLOW / Found no matching flow, creating a new flow
Phase: 2
Type: ROUTE-LOOKUP / ALLOW / in   my_DMZ    255.255.255.240 my_DMZ
Phase: 3
Type: ACCESS-LIST / ALLOW / access-group my_backbone_access_in in interface my_backbone
                                                access-list my_backbone_access_in extended permit ip any my_DMZ 255.255.255.240
Phase: 4
Type: IP-OPTIONS / ALLOW
Phase: 5
Type: ACCESS-LIST / ALLOW / access-group my_DMZ_access_out out interface my_DMZ
                                                access-list my_DMZ_access_out extended permit ip any object-group host_group
                                                object-group network host_group
                                                network-object host myHost
Phase: 6
Type: IP-OPTIONS / ALLOW
Phase: 7
Type: FLOW-CREATION / ALLOW / New flow created with id 7342770, packet dispatched to next module
Phase: 8
Type: ROUTE-LOOKUP / ALLOW / found next-hop myHost using egress ifc my_DMZ
                                                    adjacency Active
                                                    next-hop mac address 00bb.ccdd.eeff hits 1
Result:
input-interface:   my_backbone / input-status: up / input-line-status: up
output-interface: my_DMZ / output-status: up / output-line-status: up
Action: allow
As you can see it is a complete path. But this is what happens if I try it for A/9001 to B/5432:
Phase: 1
Type: FLOW-LOOKUP / ALLOW / Found flow with id 12, using existing flow
Module information for forward flow: snp_fp_inspect_ip_options, snp_fp_adjacency, snp_fp_fragment, snp_ifc_stat
Module information for reverse flow: snp_fp_inspect_ip_options, snp_fp_adjacency, snp_fp_fragment, snp_ifc_stat
Result:
input-interface: my_backbone / input-status: up / input-line-status: up / Action: allow
Apparently the packet is send into an existing flow (is there a command to see what this flow is?) and that is where it ends. Now I need to find out why this is happening... This firewall has been reloaded a few times, but that did not solve the problem. Any pointers are highly appreciated as was this hint.
Frank

Java NIO - UDP packets

I'm curious as to the rationale behind having a DatagramPacket class and just using ByteBuffers for TCP connections. I can see the logic, but I'm trying to write a Java framework wrapping NIO with TCP and UDP connections. In my C++ version I have one packet class that I use for both types of connections. I'm stuck with what to implement for Java as I'm going to need two classes, NIO's DatagramPacket and a new TCPPacket. Ideally I would like both to implement an interface or derive from a parent class so I can pass them to all class methods that deal with packets, be they UDP or TCP based. But this won't work. I could wrap DatagramPacket into a new class, and have it and the TCPPacket class implement a Packet interface. But when I'm sending UDP packets I'll be creating two objects for the price of one.
Any suggestions?
Thanks

Remember that in UDP case you can easily lose packets and never know. In TCP you would receive an exception, but UDP can silently discard your packages while in transit.
My point is, you probably should use a different package class for UDP anyway, maybe adding some stuff like a package ID that would enable re-sending and additional processing in order to ensure a successful communication.
If you already have this information and some procedures for retrying in your package, then I agree with the previous poster in that you can use bytebuffer for both.

Can't read UDP packets

Hi everyone. I'm triying to read the UDP packets that a board with a CPU and ethernet module is sending me via ethernet connection. In the board I've just implemented a static IP+UDP packet that only needs to change the data in order to send a temperature that the board measures. The packets are sent well and I can see them with a sniffer software like Wireshark like UDP packets with all the IP's, MACs and that stuff. The problem is that in Labview I'm not capable to read that data, even I can't read anything. I tried the UDP open + UDP read specifiying the destination port (40056 in my case).
Any help please???
Although, I wanted to ask if the destination IP is strictly necessary if you specify the MAC adress.
Thank you

CarlosSp wrote:
Hi everyone. I'm triying to read the UDP packets that a board with a CPU and ethernet module is sending me via ethernet connection. In the board I've just implemented a static IP+UDP packet that only needs to change the data in order to send a temperature that the board measures. The packets are sent well and I can see them with a sniffer software like Wireshark like UDP packets with all the IP's, MACs and that stuff. The problem is that in Labview I'm not capable to read that data, even I can't read anything. I tried the UDP open + UDP read specifiying the destination port (40056 in my case).
Any help please???
Although, I wanted to ask if the destination IP is strictly necessary if you specify the MAC adress.
Thank you
Please post the code you are working with.
A pictue is worth a thousand words in LV.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Cisco CSM: Duplication of udp packets possible instead of load balancing?

Hi all,
Does anybody know if it's possible to use the csm (WS-X6066-SLB-APC, OS 4.3.1) to duplicate udp packets to several real servers instead of balancing them.
In our special case we want to test duplicating snmp traps to several network management systems whereas on the snmp clients only one target address (the vserver address) is configured.
Many thanks in advance,
Thorsten

Hi Thorsten,
I'm afraid this is not possible. With the CSM you can only load-balance.
Regards
Daniel

Sending udp packets using java and receiving it using c

hi,
Is it possible to send udp packets using java and receive the same using c??????? if yes.... plz help immediately.

The biggest issue is data format. The JVM is big endian, with 16-bit characters. The machine running 'C' could be almost anything. A (signed!) byte array is probably the easiest unit of exchange.
The Java program has its own techniques for storing/retrieving data to/from the byte array - and the C program has its own techniques. ASCII Strings are often the easiest to exchange - just convert the java String objects to byte array and send them.
apaliwal1 has already given the UDP calls to send/receive the data.

How can I disable SSDP UDP packets in Firefox nightly?

Recently I started using the Firefox e10s nightlies. I notice they send out SSDP UDP packets. How can I disable Firefox SSDP? Thanks
gecko.buildID = 20141114030206
gecko.mstone = 36.0a1

I'm not seeing anything in the source code.
*http://mxr.mozilla.org/mozilla-central/source/toolkit/modules/secondscreen/SimpleServiceDiscovery.jsm
*https://tools.ietf.org/html/draft-cai-ssdp-v1-03

UDP Packet Basic

Now i'm doing socket programming using UDP and TCP/IP and now again i
need your help.
1. Can UDP packet in Java put into data structure like C? or packet map to a java object but sender is not using Java program or serialize object.
2. What is the easiest way to extract the UDP packet in Java?
assume the structure like this.
sampleMessageHeader
MessageCode UInt 16
TimeStamp UInt 32
Message Char(12)

1. Serialisation - no problem. However, if the other end doesn't have a Java serialisation library (i.e. isn't using Java) then you'll have to serialise manually. (Well - it may be possible to find documentation on the serialisation format and strip the headers before you put the bytes into a UDP packet, but such a mechanism would be a mess and a headache).
2. packet.getData() gives you a byte[]. Wrap a ByteArrayInputStream round it, and a DataInputStream around that. Then assuming appropriate byte-ordering you'll be able to read ints and shorts. Of course, Java doesn't have a UInt type, and the meaning of Char depends on your C header files.

OS/X unresponsive while broadcasting to UDP port 2223

At least once a week I have to power-cycle the iMac my kids use for their homework, because they cannot wait the few hours it takes to recover by itself.
During that time all we get from the iMac is the rainbow wheel of death,
and on the network I can see it is sending broadcasts to UDP port 2223 (rockwell-csp3). It also insists on sending NetBIOS name lookups - (despite nothing in the system preferences saying to use anything but DNS), installing a samba server on the network at least provides something to answer those lookups (but it shouldn't be necessary).
I'm guessing that the Microsoft Office (2008) installed on the machine is somehow responsible - but a computer that is catatonic for hours at a time is useless.
Anyone know of anything I can do to stop this, or something I can put on the network (other than a windows machine), that might make it happy?

Is there a chance that someone has installed some kind of
software on the computer that is trying to "call home?"
The app known as Little Snitch can tell what may be in there
and if it is responsible for these odd network calls out.
How is the port security set up in the Mac? And why would
those ports need to be open unless there was a real purpose?
With my Macs, all of the ports in Firewall are closed to access
except for the Network Time Server to keep the clock correct.
{Some are used to share files between computers, & to chat; etc.}
Do you have more than two user accounts in the computer, and
if so, is your Admin account only used to update and maintain
the OS X & to install apps for other users? The levels of security
in Mac OS X can be controlled; and such odd port calls if or when
there is no need, are signs that something is not quite right.
Have you looked into the Console utility to see what is causing the
hang at those time intervals you know this has happened? There
are several different logs and reports in there; some won't apply.
Do the children who use the computer, have access to or know the
Admin account's password? A second user, from their account, can
install software and do other things, if that password is available.
I noticed you had a similar post last month that appeared to go without
a reply; now it is locked and can't be replied to anyway. So this issue
has been going on for some time. What may have happened in the past
year or so, to start this issue in that computer? Something, for certain.
Good luck & happy computing!

UDPevent? What should I use to make an event when an UDP packet arrives?

every time my machine gets an UDP packet I need to write out the time(within millisec), and therefor I need to find an eventnotifier of some kind that checks for UDP packets arriving..

oki.. so I'm building a class for reciving the packets.. I guess i should use a thread since my program allredy is reciving these packets whit JMF - reciveStream.
now the problem is, how do I write out the time for each packet, i cant seem to find any events i can use for this, and as far as I can see, the datagarmsocket is listening for the packets and doing something with them(**) without somewhere for me to put the: System.out.printeln(time);
(**) I am going to write the packets to a file and parse it for the sequence numbers, how do I do this?

Broadcast a UDP packet

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