cs2307protoarp

7/25/2019 cs2307protoarp

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CS2307 Network Lab Socket Programming

http://cseannauniv.blogspot.com Vijai Anand

Exp# 5C ARP Client/Server

Aim To know the physical address of a host when its logical address is known using ARP

protocol.

Algorithm

Target/Server

1. Create a server socket.2. Accept client connection.

3. Read IP address from the client request

4. Check its configuration file and compare with its logical address.

5. If there is a match, send the host physical address.

6. Stop

Client

1. Create a socket.

2. Send IP address to the target machine

3. Receive target's response

4. If it is a MAC address then display it and go to step 6

5. Display "Host not found"

6. Stop

Result

Thus using ARP protoocl MAC address is obtained.
http://cseannauniv.blogspot.com/http://cseannauniv.blogspot.com/


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Program

//ARP Server -- arpserver.javaimport java.io.*;

import java.net.*;

class arpserver{

public static void main(String args[])throws IOException

{

try

{

ServerSocket soc = new ServerSocket(2500); System.out.println("Server started");

Socket client = null;

client = soc.accept(); String str;

PrintStream ps = newPrintStream(client.getOutputStream());

BufferedReader br = new BufferedReader(new InputStreamReader(client.getInputStream()));

Runtime r = Runtime.getRuntime();

Process p = r.exec("ifconfig eth0");

BufferedReader pin=new BufferedReader(new

InputStreamReader(p.getInputStream()));

String haddr = "";

String ipaddr = br.readLine(); int flag = 0;

while((str = pin.readLine())!=null) {

System.out.println(str);

if((str.indexOf("HWaddr")) != -1)

{

int tlen = str.length();

int hlen = tlen - 19;

haddr = str.substring(hlen,tlen); }

else if ((str.indexOf(ipaddr)) != -1)

{ flag = 1;

} }

if (flag == 1)

ps.println(haddr);

ps.close();

br.close();

pin.close();

client.close();


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soc.close();

}

catch(IOException io)

{

System.err.println("Exception : " + io.toString());

}

}}

//ARP Client -- arpclient.java

import java.io.*;

import java.net.*;

class arpclient

{ public static void main(String args[])

{

try {

Socket client = new Socket("localhost", 2500); BufferedReader br = new BufferedReader(new

InputStreamReader(System.in)); PrintStream ps = new

PrintStream(client.getOutputStream());

String ipaddr,haddr = null;

BufferedReader sin = new BufferedReader(new

InputStreamReader(client.getInputStream()));

System.out.print("Enter the IP address : ");

ipaddr = br.readLine(); ps.println(ipaddr);

haddr = sin.readLine(); if (haddr == null)

System.out.println("Host does not exist"); else

System.out.println("Physical Address " + haddr);

ps.close(); br.close();

client.close();

} catch(IOException io)

{ System.err.println(io.toString());

}

}}


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Output

Server

$ javac arpserver.java

$ java arpserverServer startedeth0 Link encap:Ethernet HWaddr B8:AC:6F:1B:AB:06 inet addr:172.16.6.21 Bcast:172.255.255.255 Mask:255.0.0.0 inet6 addr: fe80::baac:6fff:fe1b:ab06/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:450 errors:0 dropped:0 overruns:0 frame:0

TX packets:127 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000 RX bytes:48118 (46.9 KiB) TX bytes:21025 (20.5 KiB) Interrupt:16

Client

$ javac arpclient.java

$ java arpclient

Enter the IP address : 172.16.6.21

Physical Address B8:AC:6F:1B:AB:06

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