Chapter 6, "Access List Introduction," introduced you to the concept of access control lists (ACLs) and their uses. An ACL most commonly is used for traffic filtering. This chapter focuses on different types of ACLs that you can use for this purpose: standard, extended, named, and timed. I also discuss some additional features of ACLs, such as ACL remarks, compiling ACLs, and sequenced ACLs.
The second half of this chapter covers some of the common types of attacks that you will face and how to use an ACL to filter this offensive traffic. I even discuss how to block some common Internet applications, such as Instant Messenger and file-sharing programs (Kazaa and the sort), to keep your users in line with work-related instead of fun-related or illegal tasks.