At the lowest level, setting the Java system properties jcsi.kerberos.debug to the value true and idm.spnego.debug to the value true should produce logging to the standard error output stream.
VSJ Servlet Filter is configured on a per web application basis. This configuration is based upon log4j and defined in the Web applications web.xml deployment descriptor.
VSJ WebLogic Edition is configured through the WLS administration console by creating and adding the Default Audit Provider in the Realms -> Providers -> Auditing menu.
VSJ WebSphere Edition logging is configured through the WAS administration through the Troubleshooting -> Logs and Trace -> servername -> Modify menu.
VSJ JBoss Edition integrates with the Log4J logging framework used by JBoss. The Log4J configuration file can be found at ${jboss.home}/server/${jboss.server}/conf/log4j.xml.