Anti-Spam Design Notes
This section covers “rules” you may want to consider when designing an anti-spam solution. They are by no means “hard and fast,” but you should think about them when designing an anti-spam system.
There are as many different ways to architect an anti-spam solution as there are people who run mail systems. Each organization’s computing environment is different, and every organization has different goals, so it is very difficult to generalize. However, it is worthwhile mentioning some common themes when setting up an anti-spam solution.
Reject spam at edges of the network whenever possible— In order to lessen the amount of spam your infrastructure has to deal with, it is always best to reject known spam as ...