In this chapter, we have examined the various ways that proxy technology can be used to secure your perimeter. We described how proxies work as well as some of their advantages and disadvantages. We also discussed proxy caching, how it can be used to accelerate network performance, provide secure remote access, and offer anonymity services.
Proxies can provide unparalleled network protection. They are considered by many to be the most secure type of firewall, providing better application layer protection than other techniques, including excellent protection against attacker network-discovery methods. The commercial firewall market, though, seems to be moving away from pure proxy solutions. Their perceived inflexibility and performance limitations have relegated them to smaller roles within many networks. That being said, keep in mind that many security techniques and services can be employed together to complement and enhance each other's capabilities. When used where they make the most sense, proxies can still provide tremendous value.