You can use the command-line script iisweb.vbs, which is
stored in systemroot\System32, to stop a web site from responding. The web site
will be inaccessible to users until the site is restarted again. You can run
this command as following:
IISWeb /stop "mysite.tld"
To find more about the parameters run this:
IISWeb /stop /?
To read more about this, visit the following page: