CISCO: DoS Prevention

Here is the link:
http://www.ciscopress.com/articles/article.asp?p=345618&rl=1

This is a excerpt from the book Cisco Firewall Router Security

A Denial-of-Service (DOS) attack can cause immense harm to your business. In this chapter, you can learn how to deal with such an attack, and minimize the damage done.

There are links to other chapters, but this excerpt will give you some information on detecting DoS attacks, on implementing ACLs, and tuning IP settings to help prevent or at least survive as DoS attack.