Technical data

Enterprise Data Center Topology: J2EE Applications
1-4 Advanced Topologies for Enterprise Deployments
computers in the J2EE Business Logic DMZ tier. To increase performance and
availability, the mod_oc4j module in Oracle HTTP Server performs load
balancing and failover.
■ Another set of computers runs Oracle Application Server Single Sign-On and
Oracle Delegated Administration Services.
Oracle Application Server Single Sign-On authenticates internal and external
users, and Oracle Delegated Administration Services enable users to edit their
profiles in the Oracle Internet Directory.
mod_plsql: If you need the Web servers to invoke mod_plsql applications stored in the
customer database, you do not need the J2EE firewall (compare Figure 1–1 and
Figure 1–2). The main purpose of the J2EE firewall is to block SQL*Net access from
Web servers to the intranet. If you are using mod_plsql, which uses SQL*Net, then you
do not want the messages blocked.