In this section you are asked to define the Trusted Interface and the Untrusted Interface. Generally, the "Trusted" interface is the one that is connected to your internal network and the "Untrusted" interface is the one that is connected directly to the Internet.
The firewall rules that are in effect block all incoming Windows Networking, DHCP and syslog communication from the outside as well as translate external requests for services by internal workstations using Network Address Translation.