We are rolling out a site for a client using IIS tomorrow.
I am to take the site down to the general public (Sorry, we are updating message) and allow the client to test over the weekend after we perform the upgrade.
If it is successful, I open it to everbody - if not, I rollback.
What is the easiest way to put a "We're not open" sign for the general public, but leave the rest open to testers?