IIS: IE doesn't auto authenticate

I've been doing a little web development work recently with MVC and have come across a (very) minor issue when deploying this to my test server.

Essentially, I've deployed to the application to the server but when I access it via the IP Address, I get prompted for my windows credentials. However, when accessing it via server name I am not prompted and I get the (much better) user experience of auto authentication.

It appears that the issue is not with IIS or my MVC app but with my browser and the way it handles different URL patterns. When accessing it via server name (eg HTTP//Servername/App) the browser "knows" the site is internal so automatically authenticates whereas the IP address (HTTP//1.1.1.1/App) could be external and so throws the prompt.

Its explained here in David Wang's blog.