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Wake On Lan sample for C#

, 27 Oct 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);
 }

License

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maxburov

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Comments and Discussions

 
QuestionNot working on my system.. PinmemberMember 1002944612-May-13 22:58 
GeneralWorks with WOW PinmemberDavid j rundle15-May-12 4:34 
GeneralThanks! PinmemberAnthraxx NL22-Jan-10 10:33 
GeneralOther example and some theory Pinmembermemos-software24-Jun-08 20:31 
GeneralError PinmemberChristian Rasmussen11-Jun-08 3:11 
GeneralRe: Error PinmemberIan_E15-Jun-08 12:35 
You are using conflicting terminology in your query. An "external machine within the network"... Which is it?
 
Same Subnet
If you mean a different machine on the same subnet (i.e. behind the same router):
 
1. Verify that the MAC address you have is correct.
 
2. Verify that the machine you're trying to wake supports Wake on LAN ("WOL") functionality:
 
2A. BIOS Settings
Go into the machine's BIOS and look for a setting that enables WOL.
 
2B. Is Your Power Supply Compatible?
Note that your machine's power supply must also support this capability; if your power supply does not have its own "master" on/off switch, it's likely that it's not compatible. Modern power supplies supply a trickle voltage to the computer's motherboard (in "active off" mode); this is routed to the Ethernet adapter, among other things.
 
2C. Is Wake On LAN Configured in Windows (Windows XP assumed below)
a) In Windows, go into Control Panel & bring up Network Connections.
b) Right-click the Network Adapter corresponding to the MAC address you're trying to wake, & click "Properties".
c) In the Properties dialog, click the "Configure..." button (next to the adapter name).
d) In the "Connection Properties" dialog, look for a Power Management (or similarly named) tab. (This may or may not be there and the name will vary, depending on the manufacturer of your Ethernet adapter & the driver you have installed.)
e) If you do have a Power Management tab, look for options that enable/disable any of the following:
 
- "Wake on Directed Packet"
- "Wake on Magic Packet"
- "Wake on Magic Packet from power off state"
- "Wake on Link"
 
These are what I have for an Intel PRO/1000 Ethernet adapter on my machine. You would need to enable the 2 Wake on Magic Packet options (I leave the other 2 disabled).
 
2D. Note also that for certain add-in Ethernet adapters (PCI) and mother boards you may need to connect a 3-wire "WOL Cable" (from header on card to header on motherboard) for the WOL Capability to work. You would generally find this on really old cards & motherboards (more than 5 years old).
 
Finally, a note about states:
S1 = On (Operational)
S3 = Standby (enable "Wake on Magic Packet" to allow wakeup from this state)
S5 = Active Off (enable "Wake on Magic Packet from power off state" to allow wakeup from this state)
 
Different Subnet
If you mean a machine on a different subnet and your magic packet has to be passed outside your local router, I doubt that this is possible. I have read elsewhere that routers do not forward broadcast packets. If it's a router that you control in your own domain, you *may* be able to configure it to do so - someone else would need to comment on this possibility.
GeneralRe: Error PinmemberRandy_Miller12-Jul-08 6:14 
GeneralThanks! Pinmemberdevcow11-Jun-07 7:16 
GeneralWorks great ! PinmemberA.J.Bauer11-Mar-07 6:32 
Generalfor broadcasting Pinmemberplato2926-Jun-06 22:16 
Generalbroadcasting Pinmemberplato2926-Jun-06 21:42 
GeneralIP Broadcasting PinmemberSave My Soul - (SMS)27-Dec-05 22:29 
GeneralThanks for the sample PinmemberRadoslav Bielik6-Jan-04 11:05 

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