I've got a GAE application where I want customers to sign in from domain.com in addition to sub.domain.com, sub2.domain.com, etc. I've produced an application that limits customers to sign in from domain.com, however after i make use of the code:

<a href="<%= userService.createLoginURL(request.getRequestURI()) %>">Sign in</a>

Customers are come to a login page that limits admission to ___@domain.com and for that reason doesn't allow customers at sub.domain.com to go in within their emails and passwords to sign in.

How do i start causeing this to be possible?

It may sound as if you produced your application with authentication set to simply allow customers on 'domain.com'. You have to produce a new application set to make use of Google Account authentication, that will allow any user having a Google account to sign in. Then, you are able to restrict access in software according to their domain.

Ok, so the reply is to recreate the applying (yes, having a different title -- arg!) and to find the last authentication option: OpenID. But this may mean you need to put code inside your application to guarantee the people signing in are the type you need to sign in!