Yes, it sounds like my "I'd be surprised if it were a mod_jk issue" was hasty. Your logs show the JBoss-side session management code doing what it's supposed to -- the session has .tomcat2 appended, but a request goes to tomcat1 anyway. And then .tomcat1 does what it's supposed to do and changes the appended jvmRoute to tomcat1. So yeah, looking through the JK logs is the way to go. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4160249#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...