网络高手请进！！！(100分)

如何读取现正在使用的拨号(我和连接)的拨号网段?
我们可以判断现是否连网，可是如何知道是使用哪一个网段?
比如现使用的是163上网还是8169上网呢？

??

你是怎么判断是否已经连网的？如果是通过局域网上网的，你能否检测得出来？
我现在正在做这方面的程序，请帮忙，我会给分的！

ping一个已知的站点，就可以得到自己的IP并是否连通

to iie:
这个方法太不科学了

//你是怎么判断是否已经连网的？
interface
uses
Windows, SysUtils, Registry, WinSock, WinInet;

type
TConnectionType = (ctNone, ctProxy, ctDialup);

function ConnectedToInternet : TConnectionType;
function RasConnectionCount : Integer;


implementation

//For RasConnectionCount =======================
const
cERROR_BUFFER_TOO_SMALL = 603;
cRAS_MaxEntryName = 256;
cRAS_MaxDeviceName = 128;
cRAS_MaxDeviceType = 16;
type
ERasError = class(Exception);

HRASConn = DWord;
PRASConn = ^TRASConn;
TRASConn = record
dwSize: DWORD;
rasConn: HRASConn;
szEntryName: Array[0..cRAS_MaxEntryName] Of Char;
szDeviceType : Array[0..cRAS_MaxDeviceType] Of Char;
szDeviceName : Array [0..cRAS_MaxDeviceName] of char;
end;

TRasEnumConnections =
function (RASConn: PrasConn; { buffer to receive Connections data }
var BufSize: DWord; { size in bytes of buffer }
var Connections: DWord { number of Connections written to buffer }
): LongInt; stdcall;
//End RasConnectionCount =======================


function ConnectedToInternet: TConnectionType;
var
Reg : TRegistry;
bUseProxy : Boolean;
UseProxy : LongWord;
begin
Result := ctNone;
Reg := TRegistry.Create;
with REG do
try
try
RootKey := HKEY_CURRENT_USER;
if OpenKey('/Software/Microsoft/Windows/CurrentVersion/Internet settings',False) then begin
//I just try to read it, and trap an exception
if GetDataType('ProxyEnable') = rdBinary then
ReadBinaryData('ProxyEnable', UseProxy, SizeOf(LongWord) )
else begin
bUseProxy := ReadBool('ProxyEnable');
if bUseProxy then
UseProxy := 1
else
UseProxy := 0;
end;
if (UseProxy <> 0) and ( ReadString('ProxyServer') <> '' ) then Result := ctProxy;
end;
except
//Obviously not connected through a proxy
end;
finally
Free;
end;

//We can check RasConnectionCount even if dialup networking is not installed
//simply because it will return 0 if the DLL is not found.
if Result = ctNone then begin
if RasConnectionCount > 0 then Result := ctDialup;
end;
end;

function RasConnectionCount : Integer;
var
RasDLL : HInst;
Conns : Array[1..4] of TRasConn;
RasEnums : TRasEnumConnections;
BufSize : DWord;
NumConns : DWord;
RasResult : Longint;
begin
Result := 0;

//Load the RAS DLL
RasDLL := LoadLibrary('rasapi32.dll');
if RasDLL = 0 then exit;

try
RasEnums := GetProcAddress(RasDLL,'RasEnumConnectionsA');
if @RasEnums = nil then
raise ERasError.Create('RasEnumConnectionsA not found in rasapi32.dll');

Conns[1].dwSize := Sizeof (Conns[1]);
BufSize := SizeOf(Conns);

RasResult := RasEnums(@Conns, BufSize, NumConns);

If (RasResult = 0) or (Result = cERROR_BUFFER_TOO_SMALL) then Result := NumConns;
finally
FreeLibrary(RasDLL);
end;
end;

我的机器的注册表中有：ProxyEnable一项，且为1，但是没有ProxyServer一项，所以它
总是测得我是没有上网，而实际上我是通过局域网上网的。
而另一台机子的网络配置和我是一样的，我把它的网线拔掉了，它应该是离线的，但是
注册表上并没有反应，看来这个问题也够呛！ ：（

是读网段，不是判断连接，至于连接网上有许多这样的文章可以去看看。

接受答案了.