如何在局域网中检测哪台计算机有没有开机？(100分)

在程序中如何检测哪台计算机开了机？

HUB灯.

如果他没有装防火墙，ping它。

去下一个 “代理猎手” 扫ip的
在dos下输入 ipconfig
得到 192.168.0.6 （举列）
在 “代理猎手” 扫一下 192.168.0.1-----192.168.0.255 端口139
一般没扫到ip的就开 （只是适用一般情况）

用程序怎么实现？
最好有源码：）

{
用 Delphi实现ping的例子
}
unit PingUnit;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls, StdCtrls,winsock;

type


PIPOptionInformation = ^TIPOptionInformation;
TIPOptionInformation = packed record
TTL: Byte;
TOS: Byte;
Flags: Byte;
OptionsSize: Byte;
OptionsData: PChar;
end;

PIcmpEchoReply = ^TIcmpEchoReply;
TIcmpEchoReply = packed record
Address: DWORD;
Status: DWORD;
RTT: DWORD;
DataSize: Word;
Reserved: Word;
Data: Pointer;
Options: TIPOptionInformation;
phe: pHostent;
end;
TIcmpCreateFile = function: THandle; stdcall;
TIcmpCloseHandle = function(IcmpHandle: THandle): Boolean; stdcall;
TIcmpSendEcho = function(IcmpHandle:THandle;
DestinationAddress: DWORD;
RequestData: Pointer;
RequestSize: Word;
RequestOptions: PIPOptionInformation;
ReplyBuffer: Pointer;
ReplySize: DWord;
Timeout: DWord
): DWord; stdcall;
TPingForm = class(TForm)
StatusShow: TMemo;
Panel1: TPanel;
pingedit: TEdit;
exebutton: TButton;
Label1: TLabel;
procedure FormCreate(Sender: TObject);
procedure exebuttonClick(Sender: TObject);
private
{ Private declarations }

hICMP: THANDLE;
IcmpCreateFile : TIcmpCreateFile;
IcmpCloseHandle: TIcmpCloseHandle;
IcmpSendEcho: TIcmpSendEcho;
public
{ Public declarations }
end;

var
PingForm: TPingForm; HostName:string;

implementation

{$R *.DFM}

procedure TPingForm.FormCreate(Sender: TObject);
var
WSAData: TWSAData;
hICMPdll: HMODULE;
begin
wsastartup($101,wsadata);
hICMPdll := LoadLibrary('icmp.dll');
@ICMPCreateFile := GetProcAddress(hICMPdll, 'IcmpCreateFile');
@IcmpCloseHandle := GetProcAddress(hICMPdll, 'IcmpCloseHandle');
@IcmpSendEcho := GetProcAddress(hICMPdll, 'IcmpSendEcho');
hICMP := IcmpCreateFile;
StatusShow.Text := '';
statusshow.Align := alclient;
StatusShow.Lines.Add('目的IP地址 字节数 返回时间(毫秒)');
end;


procedure TPingForm.exebuttonClick(Sender: TObject);
var
IPOpt:TIPOptionInformation;// IP Options for packet to send
FIPAddressWORD;
pReqData,pRevDataChar;
pIPEIcmpEchoReply;// ICMP Echo reply buffer
FSize: DWORD;
MyString:string;
FTimeOutWORD;
BufferSizeWORD;
begin
if PingEdit.Text <> '' then
begin
FIPAddress := inet_addr(PChar(PingEdit.Text));
FSize := 40;
BufferSize := SizeOf(TICMPEchoReply) + FSize;
GetMem(pRevData,FSize);
GetMem(pIPE,BufferSize);
FillChar(pIPE^, SizeOf(pIPE^), 0);
pIPE^.Data := pRevData;
MyString := 'Hello,World';
pReqData := PChar(MyString);
FillChar(IPOpt, Sizeof(IPOpt), 0);
IPOpt.TTL := 64;
FTimeOut := 4000;
IcmpSendEcho(hICMP, FIPAddress, pReqData, Length(MyString), @IPOpt, pIPE, BufferSize, FTimeOut);
try
if pReqData^ = pIPE^.Options.OptionsData^ then
begin
StatusShow.Lines.Add(PChar(PingEdit.Text) + ' ' +IntToStr(pIPE^.DataSize) + ' ' +IntToStr(pIPE^.RTT));
end;
except
messagedlg('没有找到该IP地址!',mtinformation,[mbok],0);
end;
pIPE^.Phe := GetHostByAddr(@FIPAddress, 4, AF_INET);
if pIPE^.Phe <> Nil then HostName:=pIPE^.Phe^.h_name;
caption:=hostname;
FreeMem(pRevData);
FreeMem(pIPE);
end;
end;

end.

谢谢大家！