Which type of firewall technology reads and analyzes the actual content of a message before forwarding to its destination?

The correct answer is proxy servers because they operate at a higher level of inspection compared to traditional firewalls. Proxy servers act as intermediaries between clients and servers, meaning they can intercept and analyze the actual content of data packets, including messages and files. By doing so, they can enforce security policies, filter out potentially harmful content, and provide anonymity for users.

In contrast, stateful and stateless firewalls primarily focus on analyzing packet headers and maintaining state information about active connections rather than delving into the content of the data being transferred. Stateful firewalls track the state of active connections and can make decisions based on the context of traffic, while stateless firewalls apply rules to individual packets without considering their state or connection history.

Routers, on the other hand, mainly function to route packets between different networks based on their IP addresses and do not perform deep content inspection. Their primary role is to direct traffic efficiently rather than analyze the specifics of the data being transferred.

Thus, proxy servers are distinctly effective for content analysis, making them the right choice in this context.