Problem Logging in to site with two names

I have a wierd website setup, because my boss doesn't want to change
who hosts our email server.

My website is hosted on site5, and has a domain name registered with
them (www.mysite1.com).
www.mysite2.net is registered somewhere else and resolves to www.mysite1.com.

When I try to login to www.mysite1.com I have no problems.
When I try to login to www.mysite2.net, I get an error from the
verify_authenticity_token method.

I'm pretty sure I'm getting this because the session isn't being
loaded from the request, becuase I need to set some configuration in
config.action_controller.session = { in my environment.rb file.

I use :active_record_store

I've tried digging around in the abstract_store.rb file to see if I
could just hardcode something into the load! method so that it would
make sure to load authenticity_token from the request into the
session.

def load!
            stale_session_check! do
              id, session = @by.send(:load_session, @env)
              (@env[ENV_SESSION_OPTIONS_KEY] ||= {})[:id] = id
              replace(session)
              @loaded = true
            end
          end

Any suggestions would be great.

I'm not entirely sure what you mean in your setup by "mysite2.net
resolves to mysite1.com". Depending on the setup, my first guess would
be that your cookies aren't getting resolved properly.

--Matt Jones