Based on what we discovered in this chapter, you saw that when we encounter a device, our success at targeting it or even targeting through it is limited by the amount of work the administrator has taken to make the device as restrictive as possible.

Despite this, there are times when administrators make mistakes, and that is part of our job as professional security testers. We have to find these existing mistakes and document them so that the client can fix them.

One of the things that we continue to see is weak filtering rules, and this is something that has been around for a long time. Despite the new products, we can still find weak filtering rules when we are testing; therefore, the last section, before we end this chapter, will deal with detecting these.

The first weak filters we will create and then test, so that we can document the results, will be those that are often encountered in a stateless filter, and that is a router. We will use our Dynamips virtual...