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 "exterior firewall". 

The box is connected to a horizontal line labelled "DMZ or perimeter 
network". Also connected to this line are two server computers labelled "bastion 
hosts/HTTP servers" and a second rectangular box labelled "interior firewall". 
The computers are above the line, and the box is below it.

The connection through the interior firewall goes to a horizontal line 
labelled "Intranet". Also connected to this line are client computers, 
server computers, and a database.