Here's a handy tool for your bucket.. DNS Report will go through your DNS entries and let you know where there are problems. Even if you're on a hosted site it's a good idea to run your domain through their tests and see what comes up. I've just tested about a dozen domains that are all being hosted through different hosting services and all of them failed at least one test.

Give it a whirl and see how your hosting company is treating your domain.. and get ready to start hassling those support folks to fix your DNS entries.. wink