Postfix/Dovecot Allows UserAccounts to send w/o Passowrd

[Nap]

Hi,
I'm finishing the setup of my mail server and want to force all sent mail to be authenicated beforehand.

I've setup my Outlook to send/recieve mail form an account I created in ISPConfig. In order to download mail, my server checks the password I supplied. However, I can send mail from Outlook on that account even when I supply the wrong password.
How/where (link is fine) do I configure a password/authentication check before sending?

Cheers,
Nap


(Possible to fix spelling mistake in Thread Title? Passowrd => Password