I was setting up my SharePoint 2013 development environment on Windows Server 2012. I upgraded two sites from SharePoint 2010 and gave each one a fully qualified DNS. While I was able to authenticate and load the sites just fine from my laptop, when I attempted to browse them directly from the development server, the site would just continue to prompt me for credentials. This made it difficult to deploy my solutions and apps directly against the development site for debugging and testing.

Upon further research, I discovered that it is actually a security feature that prevents access to a web application with a fully qualified domain name to from the host server. This is not a very popular feature on SharePoint web farms. Follow these steps to disable this feature:

*** DISCLAIMER: This will require that you modify the registry on your host server, which can be dangerous if you’re not familiar with this. Be sure to have a disaster recovery plan in place before you proceed.

  1. Click on Search and type the command Run. From the search results, click Apps and click the Run command.

  1. Type regedit into the prompt and press okay.

  1. Traverse the Registry Editor as follows: HKEY_LOCAL_MACHINE à SYSTEM à Current Control Set à Control à LSA

  1. Right click Lsa and choose New à DWord (32-bit)

  1. Name it DisableLoopbackCheck.
  2. Double-click the new DWord and change the value to 1.