On newer versions of Windows, you’ll see a message in IE’s Information Bar (the yellow thing at the top that pops down) talking about Intranet Settings. Most people just click ‘Don’t Show Me this Again’ as they try to get rid of the endless pop-ups and questions IE presents upon its first few runs. But what does this do, and what happens if you choose the wrong option?

Internet Explorer manages security through Zones. Most pages you visit will be in the ‘Internet’ zone. Other zones include Trusted Sites and Restricted Sites, and IE will adjust security settings accordingly. Finally, there’s the Intranet zone. This zone enables a few features that wouldn’t be used on the Internet, but are often used inside corporate networks and by software developers and network administrators. Perhaps most importantly, Windows Authentication is enabled in the Intranet zone. If you don’t need these features for anything, you’re better off leaving them disabled. This is the default configuration, and this is how things are left if you choose ‘Don’t Show Me this Again’ from the Information Bar.

Without Intranet settings, though, you’ll find some things might not work properly. ActiveX controls are handled differently, pages can be rendered differently, and Windows Authentication won’t work. This means that if you browse to a web server that you should have access to through Windows Security or Active Directory, you’ll be denied access (or prompted for a password). This will even happen if you’re running as an Administrator trying to access a web server running on your own machine.

To fix this, you need to enable Intranet settings. If you’re running IE for the first time, you can just click ‘Enable Internet Settings’ from the pop-up. If you’ve already chosen ‘Don’t Show Me this Again’, you’ll have to go elsewhere to make this change. Go to Tools, Options, Security. Select Local Intranet, and then click Sites.

Clear the ‘Automatically detect intranet network’ check box – you read that right, you want the box unchecked to enable Intranet settings – and review the other settings on that window.

You may have to restart IE for your changes to take effect.

At any time, you can check the zone of the site you’re browsing by looking at the status bar. If it says ‘Internet’, you’re either on a site that’s not on your Intranet or you have Intranet settings disabled. If it says ‘Local intranet’, Windows Authentication should work.