IE don't press cookies to iframe, thus some webapplication fail in this case. To fix that we need to disable cookie but use URL rewrite. In order to do that we need to config webcontainer differencely:

Tomcat - http://jf.omnis.ch/log/archives/2004/12/disabling-session-cookie-in-tomcat.html
Jetty - http://www.mojavelinux.com/blog/archives/2006/11/disabling_session_cookies_in_jetty/
Resin - http://bbs.chinajavaworld.com/thread.jspa?threadID=731779&tstart=0


By the way, if you get "java.lang.OutOfMemoryError: PermGen space", may be this blog can help - http://jroller.com/page/agileanswers?entry=preventing_java_s_java_lang#comments


Adding load balancing with just mod_proxy and mod_rewrite - http://wiki.apache.org/cocoon/LoadBalancingWithModProxy