I am wondering if someone can help me...We have a website www.mysite.com and an alias (http://subsite.mysite.com) set up  in the Admin > Site Settings. The linking structure goes back and forth between both the sites on text / image links and if they log into www.mysite.com and click on an image that brings it to http://subsite.mysite.com it logs the user out and they have to relog in on that site. Is there someway to keep them logged in on both? Has anyone come across this, what suggestions do you have. Thank you.

It is a portal alias. We have two different domains that we want pointed to that one site. But since it was developed on www.mysite.com and some people type in http://subsite.mysite.com to get to it. So when they login on the subsite some of the links on the site bring them to www.mysite.com and they get logged out and have to login again.

Steph - not sure if this has been explained to you, but the authentication works against the domain name.  The authentication works (in part) by placing a cookie onto your computer.  The cookie is prefixed with the full domain name.  So when you login with subsite.mysite.com, the cookie is for subsite.mysite.com.  If you then switch to www.mysite.com, the cookie for www.mysite.com doesn't exist, so it looks like you're logged out.  That''s not quite true - you're just logged into subsite.mysite.com and not www.mysite.com.

The solution to your problem is to stop people logging in on subsite.mysite.com - this is best achieved by putting in a 301 redirect for all subsite.* urls to redirect to www.* Urls.  This way all users will only ever log onto the correct version of the site.

Incidentally, having your site available on two different domain names can create duplicate content in search engines and effect your rankings.  So redirecting to a single subdomain will improve this as well.