This file lets CAS know where you've stored the cas.properties file which details some of the configuration options that are specific to your environment. You can specify the location of the file here. You may wish to place the file outside of the Servlet context if you have options that are specific to a tier (i.e. test vs. production) so that the WAR file can be moved between tiers without modification. /WEB-INF/config/gis.properties