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Wake On Lan sample for C#

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4.22/5 (20 votes)

Oct 28, 2003

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Wake On Lan utility using C#.

Introduction

It's strange but I failed to find on the Internet any WOL sample written in C#. So I spent some time making a program to that purpose. It's very simple but it works OK (in our intranet at least).

For waking computers, I use Magic Packet (MAC address of network adapter repeated 16 times).

The actual functionality is implemented like this:

Code

using System;
using System.Net.Sockets;

//we derive our class from a standart one
public class WOLClass:UdpClient    
{
    public WOLClass():base()
    { }
    //this is needed to send broadcast packet
    public void SetClientToBrodcastMode()    
    {
      if(this.Active)
       this.Client.SetSocketOption(SocketOptionLevel.Socket,
                                 SocketOptionName.Broadcast,0);
    }
 }
 
...
//now use this class
 //MAC_ADDRESS should  look like '013FA049'
 private void WakeFunction(string MAC_ADDRESS)   
 {
      WOLClass client=new WOLClass();
      client.Connect(new 
         IPAddress(0xffffffff),  //255.255.255.255  i.e broadcast
         0x2fff); // port=12287 let's use this one 
      client.SetClientToBrodcastMode();
      //set sending bites
      int counter=0;
      //buffer to be send
      byte[] bytes=new byte[1024];   // more than enough :-)
     //first 6 bytes should be 0xFF
     for(int y=0;y<6;y++)
        bytes[counter++]=0xFF;
     //now repeate MAC 16 times
     for(int y=0;y<16;y++)
     {
         int i=0;
         for(int z=0;z<6;z++)
         {
              bytes[counter++]= 
                  byte.Parse(MAC_ADDRESS.Substring(i,2),
                  NumberStyles.HexNumber);
              i+=2;
         }
     }

     //now send wake up packet
     int reterned_value=client.Send(bytes,1024);
 }