Set the "Frontend Host" attribute appropriately for each server.
(1) name of server
(1) via the Administration Console, Domain > Environment > Servers > Server Name > Protocols > HTTP > Frontend Host field
p30 Table 3-4, "Securing Applications"
Oracle Fusion Middleware: Securing a Production Environment for Oracle WebLogic Server, 11g Release 1 (10.3.1)
Oracle
2009-05-01
10.3.1
Prose(pdf)