I have a mail server running on my windows box and I have enabled authentication on outgoing mail because otherwise spammers take advantage of it.

In my php.ini, I have put SMTP = localhost, but I dont' know how to make it so that it can get past my mail server's authentication. Is there some argument or soemthing so I can give it the username and password to authenticate? Else I don't know how I can have my php scripts send mail.