SMTP Auth for qmail??

[qxxx]

Hello,

every spammer in the world can send spam using my server. I am receiving hundreds of bounced mails with spam I didnt send.

I thought smtp auth is activated, i am not sure:

p15198451:~ # telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 rocket.blablaa.xxx ESMTP
ehlo blabla
250-rocket.blablaa.xxx
250-STARTTLS
250-PIPELINING
250 8BITMIME

How can I activate smtp auth? or is there a way to stop qmail and just use the forwarding? (i dont want to send mails through my server, i am using googlemail for this) but want still be able to receive mails from [email protected] which is send to [email protected]

I tried to download and patch qmail with qmail but this is a big pain in the a..

thanks.