First off I'd like to say what an excellent set of tools jauthools is!

I have 2 joomla 1.5 sites in which I am using 'SSO - HTTP' in conjunction with 'System - Single Sign On' to login users based on an Apache provided REMOTE_USER variable. On one site (Joomla 1.5.13) this works great, and when I access the website and navigate to the back end I can see I have been automatically logged in twice. It looks something like the table below:

Name Group Client
myusername Super Administrator site
myusername Super Administrator administrator

On my other site (Joomla 1.5.15) the back end side of things works fine and I do not have to log in to get to the administrator section of the site. However, the front end log in is not working, and when I navigate to the back end to see who is logged in I see only the client administrator and not the client site line.

As far as I can see I have both sites configured identically and they both have latest/identical versions of jauthtools installed. I cannot figure out why everything works in one site, but only the backend SSO works on the other site.

One other difference I can see is that when looking at the SSO Plugins using the SSO Manager, the functional site displays information about the plugin type (e.g. Type A - Normal SSO Plugin), while the part-functional site is blank for type for all plugins. I cannot see a type field in the jos_plugins database for either site, so I'm not sure where this information comes from, why it's missing in one site and if it has anything to do with my problem.

If anyone might have a pointer of where I could look to solve this I would be most grateful!