I've been trying to set up jaas authentication modules.
Here's how to set up JAAS in JRun:
1) Assuming you have a JAAS module just like the one at http://java.sun.com/j2se/1.4/docs/guide/security/jaas/tutorials/GeneralAcnOnly.html
2)Put the JAAS config file "sample_jaas.config" and the folder "sample" at /<app>/WEB-INF/classes/
3)Copy and paste the code in main() of SampleAcn.java to doPost() of your servlet.
4)Add this line so that the config file can be found by the servlet: System.setProperty("java.security.auth.login.config","file://C:/program files/allaire/JRun/servers/default/<app>/WEB-INF/classes/sample_jaas.config")
5)Add jaas.jar to JRun's classpath.
6)Add the path of folder "sample" to JRun's classpath. (IMPORTANT: simply putting it inside classes is not enough, has to add path explicitly to server's classpath)