fixed_login:
  driver = plaintext
  public_name = LOGIN
  server_prompts = User Name : Password

server_condition = \
 ${if and {{eq{$auth1}{nome_utente}}{eq{$auth2}{password_utente}}}}

server_set_id = $auth1

come potete vedere , semplice semplice,

nome_utente :           pippo

password_utente :   pluto