Chapter 4. Proxy Firewalls

In this chapter, we introduce you to proxy techniques and how they have been used to create proxy firewalls. Proxy firewalls serve a role similar to stateful firewalls. Both are designed to allow or deny access between networks based on a policy. The method they use to accomplish this is very different, though. As described in the last chapter, with a stateful firewall, network connections flow through the firewall if they are accepted by the policy. This type of firewall acts like a router, passing packets through that are deemed acceptable. In contrast, a proxy firewall acts as a go-between for every network conversation. Connections do not flow through a proxy. Instead, computers communicating through a proxy establish ...

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