Proxy firewalls are proxy servers that work as gateway firewalls. They operate at the application layer between internal clients and web servers and can control and limit access to specific websites and web services.
Like proxy servers, proxy firewalls work as a mediating instance and prevent direct contact between different systems. They have their own IP addresses and receive the data packets through them, which they then forward to the destination address via a new connection. Proxy firewalls have extensive monitoring functions in which they document the connections and security problems for security management.