Protohost Scanner

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Introduction

The application that I would like to present here is called prohost scanner.

This source is just a simple idea. I read some network programming ebooks, especially Java networking. I am not an expert, but sometimes it's not as difficult as it seems. This is source code about TCP/IP concept, basic TCP/IP concept, let me explain the code.

There are 3 methods in this source.

1. Main Method

public static void main(String args[]){
    
    if(args.length>0){
    for ( int i=0;i<args.length;++i){
                String lookup = "host";
    System.out.println(lookup+(args[i]));
    }
    }else
    {
    BufferedReader in= new BufferedReader(new InputStreamReader(System.in));
    System.out.println("enter  Hostname [ IP Address], type \"exit\" to quit");
    try{
    while(true){
    String host=in.readLine();
    if(host.equalsIgnoreCase("exit")||host.equalsIgnoreCase("quit")){
    break;
    }
   System.out.println(lookup(host));
    }
    }
    catch(IOException ex){
    System.out.println(ex);
    }
    }
    }

2. Lookup Method

private static String lookup(String host){
   
        InetAddress node;
        // get bytes from ip address
        try{
        node=InetAddress.getByName(host);
        
    
        }
        catch(UnknownHostException ex){
        return "tidak ditemukan host:"+host;
        }
   if(isHostname(host)){
   return node.getHostAddress();
   
   }
   else {
   return node.getHostName();
   }
    }

3. isHostname Method

private static boolean isHostname(String host){
    // check if the host using ipv6
        if(host.indexOf(':')!=-1) return false;
        char [] ca=host.toCharArray();
        
        for(int i=0;i<ca.length;++i){
        if(!Character.isDigit(ca[i])){
        if(ca[i]!='.') return true;
        
        }
        
        }
        return false;
    }

// simple input with bufferedReader
 BufferedReader in= new BufferedReader(new InputStreamReader(System.in));
    System.out.println("enter  Hostname [ IP Address], type \"exit\" to quit"// print out th 

// gathering information about hostname
if(args.length>0){
    for ( int i=0;i<args.length;++i){
                String lookup = "host";
    System.out.println(lookup+(args[i])); 

//  check hostname using ip46 or  not 
if(host.indexOf(':')!=-1) return false;
        char [] ca=host.toCharArray();
        
        for(int i=0;i<ca.length;++i){
        if(!Character.isDigit(ca[i])){
        if(ca[i]!='.') return true; 

Full Source Code

import java.net.*;
import java.io.*;
/**
 *
 * @author Xz
 * contact : silentboy70203@gmail.com
 */
public class nslookup {
    
    public static void main(String args[]){
    
    if(args.length>0){
    for ( int i=0;i<args.length;++i){
                String lookup = "host";
    System.out.println(lookup+(args[i]));
    }
    }else
    {
    BufferedReader in= new BufferedReader(new InputStreamReader(System.in));
    System.out.println("Enter Hostname [ IP Address], type \"exit\" to quit");
    try{
    while(true){
    String host=in.readLine();
    if(host.equalsIgnoreCase("exit")||host.equalsIgnoreCase("quit")){
    break;
    }
   System.out.println(lookup(host));
    }
    }
    catch(IOException ex){
    System.out.println(ex);
    }
    }
    }
    // method main selesai    
    
    private static String lookup(String host){
   
        InetAddress node;
       
        try{
        node=InetAddress.getByName(host);       
    
        }
        catch(UnknownHostException ex){
        return "tidak ditemukan host:"+host;
        }
   if(isHostname(host)){
   return node.getHostAddress();
   
   }
   else {
   return node.getHostName();
   }
    } 
    
    private static boolean isHostname(String host){
    
        if(host.indexOf(':')!=-1) return false;
        char [] ca=host.toCharArray();
        
        for(int i=0;i<ca.length;++i){
        if(!Character.isDigit(ca[i])){
        if(ca[i]!='.') return true;
        
        }
        
        }
        return false;
    }    
}

The function of this source is to trace the hostname and nslookup a hostname.

I know that this is just a simple source. Next time, I will be using a different Graphical User Interface. For now, I think this is enough.