Enumerate All of the IP Addresses on the Network W/O ActiveDirectory

Introduction

This code gets all of the IP addresses on the network. The best part is, it doesn't use ActiveDirectory. It uses the default DOS commands for networking, specifically "net view". Also, it uses the System.Net.Dns class to resolve the IPs.

Code

private ArrayList GetIPAddresses()
{
 ArrayList Addresses = new ArrayList(); // Temp array to fill

 //Get my address

 string MyAdd = 
  Dns.GetHostByName(Dns.GetHostName()).AddressList[0].ToString();
 // Used to start the command

 System.Diagnostics.ProcessStartInfo psi = 
       new System.Diagnostics.ProcessStartInfo();
 //prompt

 psi.FileName = @"C:\WINDOWS\system32\cmd.exe"; // Path for the cmd prompt

 psi.Arguments = "/c net view > boo.txt"; // Arguments for the command prompt

 // "/c" tells it to run the following command which is "net view > boo.txt"

 // "net view" lists all the computers on the network

 // " > boo.txt" tells dos to put the results in a file called boo.txt

 psi.WindowStyle = 
  System.Diagnostics.ProcessWindowStyle.Hidden; // Hide the window

 Application.DoEvents();
 // So the computer doesn't bog down

 System.Diagnostics.Process.Start(psi); // Run

 System.IO.StreamReader sr = null; // used for boo.txt

 bool run = false; // used to tell if dos is done yet

 while(run == false) // while dos is still running

 {
  Application.DoEvents(); // let windows do it's stuff

  try
  {
   System.Threading.Thread.Sleep(1000); // wait a second

   sr = new System.IO.StreamReader(Application.StartupPath 
                   + "\\boo.txt"); // Try to open the file

   // If dos is not done yet, this will throw an error

   run = true; // If I get here, dos is done and we can use the file

  }
  catch
  {
   run = false; // Dos is not done yet

  }
 }
 // Cycle through the file until the info starts

 while(sr.ReadLine().StartsWith("--") != true) 
 {
   Application.DoEvents();
 }
 string str = ""; // filled with each line of the file

 string[] comp = new string[32]; // temp array of computer names

 int i = 0; // indexer for comp[]

 // cycle until we reach, "The command completed successfully."

 while(str.StartsWith("The") != true) 
 {
   Application.DoEvents();
   str = sr.ReadLine(); // Read the next line

  // Split the line after the first space

   comp[i] = str.Split(char.Parse(" "))[0];
   // Normally, in the file it lists it like this

   // \\MyComputer                 My Computer's Description


  // Take off the slashes, "\\MyComputer" to "MyComputer"

   comp[i] = comp[i].Substring(2, comp[i].Length - 2);
   if(comp[i] == "e") 
  // For some reason, I was getting an element

  // in this array that has the value of "e", so I took 

  // it out! lol

   {
     Application.DoEvents();
     comp[i] = null;
   }
   i++; // move to the next place in comp[]

 }
 sr.Close(); // close the file handle

 sr = null; // free memory

 foreach(string s in comp) // for every computer that we have...

 {
  if(s != null) // if there really is a computer...

  {
   if(s.ToUpper() != Dns.GetHostName().ToUpper()) 
  // if the computer is not me...

   {
    Addresses.Add(Dns.GetHostByName(s).AddressList[0].ToString()); 
  // ... add the address to the array

   }
  }
 }
 return Addresses; // return the array

}

All you have to do is call this function. E.g.:

ArrayList Adds = new ArrayList();
Adds = GetIPAddresses();