function IsPortActive(const AHost: string; APort: Word): Boolean;
var
  IdTCPClient: TIdTCPClient;
begin
  Result := False;

  IdTCPClient := TIdTCPClient.Create(nil);
  try
    try
      IdTCPClient.Host := AHost;
      IdTCPClient.Port := APort;
      IdTCPClient.Connect;
      Result := True;
    except
      // ignore exceptions [really ? are you sure ?]
    end;
  finally
    IdTCPClient.Free;
  end;
end;