I've been through the docs, and found this thread (http://ellislab.com/forums/viewthread/58566/), which makes it appears as if a user can login to site A, and also login to site B at the same time on an MSM setup. The idea being they login once, and get access to both sites and appear logged into both sites. I need this to happen on the front-end of the site, not the control panel. I followed the thread, and the docs and made the necessary configuration updates, but nothing works. I even added a hook and tried to create the cookie manually for the other domains, but I suppose thats not possible b/c its a potential XSS issue (the sites are all on different domains).
Site A, the main site, houses the registration form. If a user is on site B, they are sent to site A, register (and auto logged in), and then return to site B, however, they are not logged into site B at this point, only site A. I need them to be logged into both.
I suppose the only course of action is to create some sort of handshaking via ?ACT requests with a token to validate the login, thus each domain would receive an ?ACT request to set the cookie on that domain.
Is there any other way to approach this? Why do the native config values have no affect?