Half of Shibboleth runs within the web server. For Sun/iPlanet, this half is implemented in an NSAPI module called nsapi_shib.so or nsapi_shib.dll, depending on the platform. The initial configuration is controlled with the magnus.conf and obj.conf configuration file(s), but one of the primary options there (normally unneeded) is to point the module at the overall SP configuration file (shibboleth2.xml) where a lot of the options not specific to the web server are controlled.
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