SharePoint 2013 Prerequisite Installer fails at Web Server Role

Scenario:

You want to install SharePoint 2013 in a server that has no connection to the internet. You have downloaded all your prerequisites according to the following articles:

http://technet.microsoft.com/en-us/library/ff686793.aspx
http://technet.microsoft.com/en-us/library/cc262485.aspx

If you want an easier version (in spanish) refer to this article by Matias Rama:

http://blogs.technet.com/b/pfespain/archive/2013/08/07/sharepoint-2013-instalaci-243-n-de-requisitos-de-software-y-v-237-nculos.aspx

Symptom:

When you run the prerequisite. The process fails while trying to activate the Web App role (IIS). This also happen if you manually try to add this role to the server.

Solution

The problem, ussualy, is because the binaries are in the CD, which might be in a different drive when installed. You need to specify manually where are your binaries.

When you clic on the image, check on the message:

"Source files for .net Framework 3.5 are not installed as part of a typical installation [...]"

Put the path

E:\Source\SxS

In the text box, press ok and add the role to the server. This shouldn´t last too much.

Now you are ok to continue to install all the prerequisites.