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?

  • Unfortunately there does not seem like there's a feasible solution for this. I've looked into storing cookies, session ids and more. Some old posts I've read make it seem like this is doable, but I've never found a solution. I'd LOVE to see this! But alas I don't think we'll ever get a solution that does it. May 31, 2013 at 21:37
  • I have an MSM setup like this. I can give details next week, if no one else beats me to it. May 31, 2013 at 22:07
  • Stephen, that would be huge if you can share. I need to figure out a solution this week. Jun 3, 2013 at 13:58
  • Turns out I fibbed. Sent private message to Brian to explain my set up, which won't help him. Jun 14, 2013 at 13:46

1 Answer 1


Turns outs I was right. Since each site is on a different domain name a custom add-on to do an authorized handshake is required. If the sites were on the same domain, but in different sub-domains it would work out of the box.

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