How to Spam & mysql control ?

[nicefrid]

Some unwanted domain sending spam mail through my mail server.

I am using courier mail server.

1. Can anyone tell me how i can control like outgoing mail through my server, send mail from other domains or ip.

2. All outgoing mails going to spam folder as google, yahoo. etc..,

3. Mysql server getting more resources and my vps account is getting stuck, mysql connection get more than 100 itself.

please give solution for this 3 problems.

thanks

[nicefrid]

No one not able to give answer? or not posted in correct topic?