한결 편하긴 한데 xp 여부를 묻지 않고 제대로 되지 않는 경우가 흔한 건 마찬가지군요. upnp를 이용한 포트 포워딩을 구현하고 보니 되지 않는 경우가 잦았는데 네트워크 어댑터를 제대로 찾지 못 해 그랬던 모양입니다. ipconfig는 쉽게 잘 찾는데 파일 탐색기의 네트워크를 클릭해 봐도 공유기가 검색되지 않는 경우가 흔합니다. ipconfig 결과를 파싱하는 방법을 다시 써야 할 듯합니다.

uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Winapi.IpHlpApi, Winapi.IpTypes, Vcl.StdCtrls;

procedure TForm1.FormCreate(Sender: TObject);
var
  _AdapterInformation: PIP_ADAPTER_INFO;
  _OutBufferLength: Cardinal;
  _MACAddress: string;
  i: Integer;
begin
  _OutBufferLength := SizeOf(IP_ADAPTER_INFO);

  _AdapterInformation := AllocMem(_OutBufferLength);

  GetAdaptersInfo(_AdapterInformation, _OutBufferLength);

  for i := 0 to 5 do
  begin
    _MACAddress := _MACAddress + IntToHex(_adapterinformation.Address[i], 2);
  end;

  Memo1.Lines.Add(_MACAddress);
  Memo1.Lines.Add(string(_AdapterInformation.GatewayList.IpAddress.S));
  Memo1.Lines.Add(string(_AdapterInformation.IpAddressList.IpAddress.S));

  FreeMem(_AdapterInformation);
end;