How do I get the MAC address of a network card using Delphi?

Question

How do I get the MacAddress of an Network Card using Delphi ?

Answer 1

The GetAdaptersAddresses function is the preferred way to obtain adapters information since 2001 with Windows XP.

The adapter's information is returned in the IP_ADAPTER_ADDRESSES structure by the AdapterAddresses parameter.

The GetAdaptersAddresses function can retrieve information for IPv4 and IPv6 addresses.

The recommended method of calling the GetAdaptersAddresses function is to pre-allocate a 15KB working buffer pointed to by the AdapterAddresses parameter. On typical computers, this dramatically reduces the chances that the GetAdaptersAddresses function returns ERROR_BUFFER_OVERFLOW, which would require calling GetAdaptersAddresses function multiple times.

---

procedure TForm1.Button1Click(Sender: TObject);
const
  AF_UNSPEC = 0;
  GAA_FLAG_INCLUDE_ALL_INTERFACES = $100;
  WORKING_BUFFER_SIZE = 15000;
  MAX_TRIES = 3;
var
  pAddresses,
  pCurrAddresses: PIpAdapterAddresses;
  dwRetVal,
  outBufLen: Cardinal;
  i: Integer;
  macAddress: string;
begin
  Memo1.Lines.Clear;

  outBufLen := WORKING_BUFFER_SIZE;
  pAddresses := nil;
  i := 0;
  repeat
    if Assigned(pAddresses) then
      FreeMem(pAddresses);

    GetMem(pAddresses, outBufLen);
    if not Assigned(pAddresses) then
      raise Exception.Create('Memory allocation failed for IP_ADAPTER_ADDRESSES struct');

    dwRetVal := GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_INCLUDE_ALL_INTERFACES, nil, pAddresses, @outBufLen);
    Inc(i);
  until (dwRetVal <> ERROR_BUFFER_OVERFLOW) or (i = MAX_TRIES);

  try
    if NO_ERROR <> dwRetVal then begin
      if ERROR_NO_DATA = dwRetVal then begin
        MessageDlg('No addresses were found for the requested parameters', mtInformation, [mbOK], 0);
        Exit;
      end
      else
        raise Exception.Create(SysErrorMessage(dwRetVal));
    end;

    pCurrAddresses := pAddresses;
    while Assigned(pCurrAddresses) do begin
      if pCurrAddresses^.PhysicalAddressLength > 0 then begin
        Memo1.Lines.Add(pCurrAddresses^.FriendlyName);
        macAddress := '';
        for i := 0 to pCurrAddresses^.PhysicalAddressLength - 1 do begin
          if i > 0 then
            macAddress := macAddress + ':';
          macAddress := macAddress + Format('%.2X', [pCurrAddresses^.PhysicalAddress[i]]);
        end;
        Memo1.Lines.Add(macAddress);
        Memo1.Lines.Add('');
      end;
      pCurrAddresses := pCurrAddresses^.Next;
    end;

  finally
    if Assigned(pAddresses) then
      FreeMem(pAddresses);
  end;
end;