Selenium 2: How to check that server is running and stop the server?

With Selenium 1 there was the possibility to enter a URL to stop the server:

http://:/selenium-server/driver/?cmd=shutDown

Is there a similar way in Selenium 2?

I tried the following URL to check whether the server is running:

http://:/wd/hub/

but that only returns an HTTP ERROR 503 (service unavailable). Is there any other URL I can access to verify that the server is running?