to relay or not to relay?

[tolis]

Hi everyone,
Since last friday i saw that my qmail qeue had over 1000 mail.I checked and saw that almost 500 of them where coming ftom a domain no t in my IP and were going to a recipient not in IP too.
I thought it was relaying.I have added the domain to my black list but i need some help with the realying issue.I have an open relay but with both smtp and pop (10 min) auth. How did he get a relay despite the auths?
And if i set from my plesk 7.5.3 the relay mode to off what my clients will not be able to do?
Should i set relaying to off?
What is MAPS?
Thanks
I have choosen to have a unique IP for qmail than the one pointing to the domain.Does that matter?

 

[phoenixisp]

First off, it's not polite to cross post. Posting your problem once in the correct section will do.

That being said, you should have smtp authorization checked under Mail-Preferences, but not necessarily POP3.

MAPS is a way to have the mail server check to see if the sending server has been blacklisted. The one that I use is 'sbl-xbl.spamhaus.org'. If you have previously added the '-Rt0' argument to your smtp_psa file you will have to add it again if you enter a MAPS domain. The file will be over-written.

But more than likely somebody is using a script that's installed on the server to send the emails, something like formmail.pl. More info may be obtained by going through the mail logs at /usr/loca;/psa/var/log/maillog (redhat)