Linux Firewalls, Third Edition

Basic Gateway Firewall Setups

Two basic gateway firewall setups are used here. As shown in Figure 6.1, the gateway has two network interfaces: one connected to the Internet and one connected to the DMZ. Public Internet services are offered from machines in the DMZ network. The gateway firewall offers no services. A second firewall, a choke firewall, is also connected to the DMZ network, separating the internal, private networks from the quasi-public server machines in the perimeter network. Private machines are protected behind the choke firewall on the internal LAN. Additionally, each of the server machines in the DMZ runs a specialized firewall of its own. If the gateway firewall or one of the servers fails, the public server machines in the ...