Firewall architecture is represented by computer symbols connected by 
communication lines. At the upper left, a client computer is connected to a 
cloud labelled "Internet". Another connection to the cloud goes to a 
rectangular box directly under it labelled "interior/exterior firewall". 

The firewall box is connected by two horizontal lines to two server 
computers labelled "bastion hosts/HTTP servers". These computers are not
connected to each other outside the firewall box. This whole middle section, 
consisting of firewall, lines, and server computers, is labelled "DMZ or perimeter 
network". 

The firewall box is connected by a vertical line to a horizontal line labelled 
"Intranet". Also connected to the horizontal line are client computers, 
server computers, and a database.