Has your girlfriend cheated on you?

import java.math.BigInteger;
import java.security.MessageDigest;

public class RefCrack {
    
    public static void main(String[] args)
    {
        if (args.length != 1)
            System.out.println("usage: java RefCrack [ref-code]");
        else
            new RefCrack(args[0]);
        
    }
    
    public RefCrack(String ref)
    {        
        String ip = "1.1.1.1";
        while (!ref.equals(md5(ip)) || ip.equals("256.0.0.0"))
            ip = increment(ip);
        if (ip.equals("256.0.0.0"))
            System.out.println("bad ref code");
        else
            System.out.println("\n\nIP: "+ip);
    }
    
        public String increment(String input)
    {
        String[] s = input.split("\\.");
        int[] t = new int[4];
        t[0] = Integer.parseInt(s[0]);
        t[1] = Integer.parseInt(s[1]);
        t[2] = Integer.parseInt(s[2]);
        t[3] = Integer.parseInt(s[3]);
        t[3]++;
        if (t[3] == 256)
        {
            t[3] = 0;
            t[2]++;
            System.out.println("Checking: "+t[0]+"."+t[1]+"."+t[2]+".*");
        }
        if (t[2] == 256)
        {
            t[2] = 0;
            t[1]++;
        }
        if (t[1] == 256)
        {
            t[1] = 0;
            t[0]++;
        }
        return t[0]+"."+t[1]+"."+t[2]+"."+t[3];
    }
    
    public String md5(String input) {
        try {
        MessageDigest m=MessageDigest.getInstance("MD5");
        m.update(input.getBytes(),0,input.length());
        return new BigInteger(1,m.digest()).toString(16);
        
        } catch (Exception e) {System.out.println("md5 error"); return "";}
    }
    
    
}