HOW TO FIND THE PATH TRAVELLED BY THE CLIENT'S REQUEST PACKET

Question

Hi,
I want to know is there any way by which we can know the entire path or the hops travelled by the client request packet to reach the web-server.Say suppose the client machine is part of a large network in a corparate where there is a a personlaized WAN. I want to know whther i can achive this using the servlets.
and i even want to know some information about the client's NIC Card Physical Address.If at all i use the HttpServletRequest.inetAddress() gives the public IP of the Client which is shared in the network.
Please suggest me a way by which i can do this.
Thanks in Advance!!!
Regards,
RAHUL

Answer 1

hey i m back
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.URL;
import java.util.Arrays;
import jpcap.JpcapCaptor;
import jpcap.JpcapSender;
import jpcap.NetworkInterface;
import jpcap.NetworkInterfaceAddress;
import jpcap.packet.EthernetPacket;
import jpcap.packet.ICMPPacket;
import jpcap.packet.IPPacket;
import jpcap.packet.Packet;
public class Traceroute {
     public static void main(String[] args) throws Exception{
          if(args.length<2){
               System.out.println("Usage: java Traceroute <device index (e.g., 0, 1..)> <target host address>");
               System.exit(0);
          //initialize Jpcap
          NetworkInterface device=JpcapCaptor.getDeviceList()[Integer.parseInt(args[0])];
          JpcapCaptor captor=JpcapCaptor.openDevice(device,2000,false,5000);
          InetAddress thisIP=null;
          for(NetworkInterfaceAddress addr:device.addresses)
               if(addr.address instanceof Inet4Address){
                    thisIP=addr.address;
                    break;
          //obtain MAC address of the default gateway
          InetAddress pingAddr=InetAddress.getByName("www.microsoft.com");
          captor.setFilter("tcp and dst host "+pingAddr.getHostAddress(),true);
          byte[] gwmac=null;
          while(true){
               new URL("http://www.microsoft.com").openStream().close();
               Packet ping=captor.getPacket();
               if(ping==null){
                    System.out.println("cannot obtain MAC address of default gateway.");
                    System.exit(-1);
               }else if(Arrays.equals(((EthernetPacket)ping.datalink).dst_mac,device.mac_address))
                         continue;
               gwmac=((EthernetPacket)ping.datalink).dst_mac;
               break;
          //create ICMP packet
          ICMPPacket icmp=new ICMPPacket();
          icmp.type=ICMPPacket.ICMP_ECHO;
          icmp.seq=100;
          icmp.id=0;
          icmp.setIPv4Parameter(0,false,false,false,0,false,false,false,0,0,0,IPPacket.IPPROTO_ICMP,
                    thisIP,InetAddress.getByName(args[1]));
          icmp.data="data".getBytes();
          EthernetPacket ether=new EthernetPacket();
          ether.frametype=EthernetPacket.ETHERTYPE_IP;
          ether.src_mac=device.mac_address;
          ether.dst_mac=gwmac;
          icmp.datalink=ether;
          captor.setFilter("icmp and dst host "+thisIP.getHostAddress(),true);
          JpcapSender sender=captor.getJpcapSenderInstance();
          //JpcapSender sender=JpcapSender.openDevice(device);
          sender.sendPacket(icmp);
          while(true){
               ICMPPacket p=(ICMPPacket) captor.getPacket();
               //System.out.println("received "+p);
               if(p==null){
                    System.out.println("Timeout");
               }else if(p.type==ICMPPacket.ICMP_TIMXCEED){
                    p.src_ip.getHostName();
                    System.out.println(icmp.hop_limit+": "+p.src_ip);
                    icmp.hop_limit++;
               }else if(p.type==ICMPPacket.ICMP_UNREACH){
                    p.src_ip.getHostName();
                    System.out.println(icmp.hop_limit+": "+p.src_ip);
                    System.exit(0);
               }else if(p.type==ICMPPacket.ICMP_ECHOREPLY){
                    p.src_ip.getHostName();
                    System.out.println(icmp.hop_limit+": "+p.src_ip);
                    System.exit(0);
               }else continue;
               sender.sendPacket(icmp);
}