I want be able to send outgoing email from my website. I want to setup Win2008 smtp to be able to send them respecting all the spam rules.

My checklist is:

• the smtp should be able to accept outgoing email only from internal sites: I will limit it to relay only 127.0.0.1 is this correct?
• it should have set SPF, DKIM and all the policy avaiable to not be marked as spam: how you would configure it for the internal SMTP? Should I use another kind of server like hMail server?
• I should be able to send like 30 email from each user session on the website without obliging the user to wait that the email is effectivly sent (I thought to save it on a folder and then use a batch to send them asynchronously). What are my options?

What other steps would you add to be sure that the outgoing email is not marked as spam?