Single-signon: Login to two site at once?

I need to check if sure is logged in

1. user login to account.domain.com

2. system creates session fo开发者_Go百科r account.domain.com

   (at this point i want the user to also login to support.domain.com)

How does support.domain.com check if the user is logged into to account.domain?

  session_set_cookie_params(0, "/", ".domain.com");

note that leading dot. This functions should be called BEFORE session_start();

If you change your session cookie domain to .domain.com, then the same session will be accessible on both subdomains.

Session wont work with www