I am looking to optimize the server by doing the following.

1. DNS cacheing - *greatly* reduces the time the MTA takes to look up the receiving domain, and of course only has to do a lookup once per domain.

2. Deferred DNS lookup - the MTA accepts the email from script and looks up the DNS of the receiving domain later, saving script from hanging around.

3. One that I call "accept now, send later" - the MTA accepts email from script immediately and sends it later using a different process. Again, script isn't left hanging around while the MTA sends the mail.

4. Multiple email queues - I could set up 20 mail queues that were able to send mail simultaneously and independently of each other.

I do not know what to do as far as making these happen because I am new to Server Administration, any help would be greatly appreciated! :-)