asp.net 2.0

I have set my web.config as follows: <forms timeout="30"/> (I know that's
the default but I may chang it so the line's in there)

I also have a few cookies I'm setting on my login page to hold the UserName,
UserID and the value of another field in my db so that as the user is
navigating around the site I can test for certain things. All that seems to
be fine. I've set the cookies to expire in 30 minutes also to coordinate
wiht the login stuff in asp.net 2.

I tested all this by setting the above times to 1 minute. If I log in and go
to a page that requires login and then don't do anythign for one minute and
then try to do something that requires me to be logged in, the login page
appears again and all's good.

The problem is that I have my login link and my LoginName control on my
master page and so even after the timeout has occurred, those still indicate
the user is logged in. They don't change to the logged out state until after
I try to do some action. I'd like to update these automatically and put a
message up that says the user has been logged out when that happens. I've
been to many websites where this is done. My bank's site for example does
this. After 10 minutes of inactivity, I'm logged out and the page is updated
to reflect the fact that I'm no longer logged in. I'm presented with the
login text boxes again. How can I do this same thing? How can I
automatically update the page to show that after the timeout the user has to
log in again. Otherwise, even though the user is actually no longer
authenticated, the page seems to indicate that he's still logged in.

Thanks,

Keith