Code:

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;