Description of the illustration twotierproxyarch.gif

This graphic has on the left the label "Clients" bounded by a dotted line. To its right is a box labeled "Firewall," and to its right is a column of two-sectioned boxes labeled "HTTP Server" and "Proxy Plug-in." These boxes are surrounded by a dotted line and are labeled "Web Servers (Web tier)." The dotted line is labeled "DMZ." To the right of this column is a column of pentagons labeled "Server/Object Cluster (presentation, object tiers)." Each pentagon contains the labels "JSP," "Servlet," "EJB," and "JDBC." To the right of this column is a database.

Clients points through the Firewall to each of the HTTP Servers. Each of the HTTP Servers points as a group with three arrows to each of the pentagons and then to the database.