Write a program to demonstrate Sub-netting and find subnet masks
CNS Assignment 5
Write a program to demonstrate Sub-netting and find subnet masks
Code :
//FileName : subnet.java
import java.util.Scanner;
import java.net.InetAddress;
class subnet
{
public static void main(String args[])
{
Scanner sc= new Scanner(System.in);
System.out.print("Enter the ip address=");
String ip=sc.nextLine();
//----Split the Ip Address-------
String split_ip[] = ip.split("\\.");
//----- Converting the Ip Address to binary----
String split_bip[]= new String[4];
String bip = "";
for(int i=0;i<4;i++)
{
split_bip[i]=appendZeroes(Integer.toBinaryString(Integer.parseInt(split_ip[i])));
bip+=split_bip[i];
}
System.out.println("The binary IpAddress is="+bip);
//----- Finding the Subent mask-----
System.out.println("Enter the number of address");
int n=sc.nextInt();
int bits=(int)Math.ceil(Math.log(n)/Math.log(2));
System.out.println("The number of bits required="+bits);
int mask=32-bits;
int total_address=(int)Math.pow(2,bits);
System.out.println("Subnet mask is "+mask);
//---- Finding the first and last address----
//---- First address Calculation--------
int fbip[]=new int[32];
for(int i=0;i<32;i++)
{
//Convert to the character 1,0 to integer 1,0
fbip[i]=(int)bip.charAt(i)-48;
}
for(int i=31;i>31-bits;i--)
{
//Get first address by anding the last bits with 0
fbip[i] &=0;
}
String fip[]={"","","",""};
for(int i=0;i<32;i++)
{
fip[i/8]=new String(fip[i/8]+fbip[i]);
}
int first_offset=0;
int ipAddr[]=new int[4]; ;
System.out.println("Group 1 \nThe First Address is:");
for(int i=0;i<4;i++)
{
System.out.print(ipAddr[i]=first_offset=Integer.parseInt(fip[i],2));
if(i!=3)
System.out.print(".");
}
System.out.println();
//--- Last address Calculation----
int lbip[]=new int [32];
for(int i=0;i<32;i++)
{
// Convert the character 1,0 to integer 1,0
lbip[i]=(int)bip.charAt(i)-48;
}
for(int i=31;i>31-bits;i--)
{
// Get last address by oring with last bits with 1
lbip[i]|= 1;
}
String lip[]={"","","",""};
for(int i=0;i<32;i++)
{
lip[i/8]=new String(lip[i/8]+lbip[i]);
}
int ipLast[]=new int[4];
System.out.println("The Last Address is:");
for(int i=0;i<4;i++)
{
System.out.print(ipLast[i]=Integer.parseInt(lip[i],2));
if(i!=3)
System.out.print(".");
}
System.out.println();
System.out.println("How many subnets do you want to form?");
int scount=sc.nextInt();
for(int j=1;j<scount;j++)
{
System.out.println(" GROUP "+ (j+1)+" FIRST ADDRESS:");
for(int i=0;i<4;i++)
{
if(i<3)
{
System.out.print(ipAddr[i]+".");
}
else
System.out.println(ipAddr[i]=ipAddr[i]+total_address);
}
System.out.println(" GROUP "+ (j+1)+" LAST ADDRESS:");
for(int i=0;i<4;i++)
{
if(i<3)
{
System.out.print(ipLast[i]+".");
}
else
System.out.println(ipLast[i]=ipLast[i]+total_address);
}
System.out.println();
}
try
{
System.out.println("Enter the Ip address to ping=");
Scanner s=new Scanner(System.in);
String ip_add=s.nextLine();
InetAddress inet = InetAddress.getByName(ip_add);
if(inet.isReachable(5000))
{
System.out.println("The ip address is reachable"+ip_add);
}
else
{
System.out.println("The ip address is not reachable "+ip_add);
}
}
catch( Exception e)
{
System.out.println("Exception:"+e.getMessage());
}
}
static String appendZeroes(String s)
{
String temp= new String("00000000");
return temp.substring(s.length())+ s;
}
}
Output
Code
//FileName : subnetmask.java
import java.util.Scanner;
public class subnetmask {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String ip = new String();
int mask=0,defaultmask=0;
System.out.println("enter ip address");
ip = scan.nextLine();
System.out.println("enter mask");
mask = scan.nextInt();
String[] splitip = ip.split("\\.");
System.out.println(splitip[0]+" "+splitip[1]+" "+splitip[2]+" "+splitip[3]+" ");
int first = Integer.parseInt(splitip[0]);
if(first>=0&&first<=127){
System.out.println("CLASS A");
defaultmask = 8;
}
else if(first>127&&first<=191){
System.out.println("CLASS B");
defaultmask=16;
}
else if(first>191&&first<=223){
System.out.println("CLASS C");
defaultmask=24;
}
else if(first>223){
System.out.println("CLASS D");
defaultmask=32;
}
String binip = new String();
String defmask = new String();
for(int i=0;i<4;i++){
binip = binip +
appendZeroes(Integer.toBinaryString(Integer.parseInt(splitip[i])));
}
System.out.println("IP in binary : "+binip);
System.out.println("Default Mask : "+defaultmask);
for(int i=0;i<32;i++){
if(i<mask){
defmask = defmask + "1";
}
else{
defmask = defmask + "0";
}
}
System.out.println(defmask);
String netid = new String();
for(int i=0;i<32;i++){
netid = netid +
(Integer.parseInt(""+binip.charAt(i))&Integer.parseInt(""+defmask.charAt(i)));
}
int p=-1;
System.out.println(netid);
String[] net = new String[4];
String[] def = new String[4];
for(int i=0;i<32;i++){
if(i%8==0){
p++;
net[p] = "";
def[p]="";
net[p] = net[p] + netid.charAt(i);
def[p] = def[p] + defmask.charAt(i);
}
else{
net[p] = net[p] + netid.charAt(i);
def[p] = def[p] + defmask.charAt(i);
}
}
System.out.println("Given IP : "+ip);
System.out.print("subnet mask :");
for(int i=0;i<4;i++){
System.out.print(Integer.parseInt(def[i],2));
if(i!=3)
System.out.print(".");
}
System.out.println();
System.out.print("NetId : ");
for(int i=0;i<4;i++){
System.out.print(Integer.parseInt(net[i],2));
if(i!=3)
System.out.print(".");
}
}
private static String appendZeroes(String binaryString) {
// TODO Auto-generated method stub
/*if(binaryString.length()<8){
for(int i=0;i<8-binaryString.length();i++){
binaryString = "0" + binaryString;
}
}*/
String temp = new String("00000000");
return temp.substring(binaryString.length())+ binaryString;
}
}
Output
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