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The value of a element specifies the JNDI name of the security manager interface implementation that JBoss uses for the EJB and web containers. This is an object that implements both of the AuthenticationManager and RealmMapping interfaces. When specified as a top-level element, it defines what security domain is specified for all EJBs in the deployment unit. This is the typical usage because mixing security managers within a deployment unit complicates inter-component operation and administration.