[Exim] SMTP authentication

Hi,

i want to use smtp authentication in exim-4.10, and i put
these lines in the exim.conf file:

plain:
driver = plaintext
public_name = PLAIN
server_condition = "${if
crypteq{$3}{${extract{1}{:}{${lookup{$2}lsearch{/etc/exim/passwd}{$value}{*:*}}}}}{1}{0}}"
server_set_id = $2



but when my e-mail client connect to the smtp to send
messages, authentication are not solicited.

Is there any solution to this?

Thanks a lot

Bruno Couto.