Application Server Role, Web Server (IIS) Role: configuration error

I’m installing SharePoint 2013 on Windows 2012 ‘offline’ – the server has no Internet access.  Within minutes of starting the Preparation Tool to install the prerequisites it has failed to install the Web Server (IIS) Role.

The process failed because additional files are required and the server does not have access to Windows Update.  I’ve got around this by installing the role manually using a few PowerShell commands, namely Add-WindowsFeature, specifying the Windows 2012 DVD as the installation source (the server is virtual so I have mounted the ISO image).  The commands are as follows:

Import-Module ServerManager

Add-WindowsFeature NET-WCF-HTTP-Activation45,NET-WCF-TCP-Activation45,NET-WCF-Pipe-Activation45

Add-WindowsFeature Net-Framework-Features,Web-Server,Web-WebServer,Web-Common-Http,Web-Static-Content,Web-Default-Doc,Web-Dir-Browsing,Web-Http-Errors,Web-App-Dev,Web-Asp-Net,Web-Net-Ext,Web-ISAPI-Ext,Web-ISAPI-Filter,Web-Health,Web-Http-Logging,Web-Log-Libraries,Web-Request-Monitor,Web-Http-Tracing,Web-Security,Web-Basic-Auth,Web-Windows-Auth,Web-Filtering,Web-Digest-Auth,Web-Performance,Web-Stat-Compression,Web-Dyn-Compression,Web-Mgmt-Tools,Web-Mgmt-Console,Web-Mgmt-Compat,Web-Metabase,Application-Server,AS-Web-Support,AS-TCP-Port-Sharing,AS-WAS-Support, AS-HTTP-Activation,AS-TCP-Activation,AS-Named-Pipes,AS-Net-Framework,WAS,WAS-Process-Model,WAS-NET-Environment,WAS-Config-APIs,Web-Lgcy-Scripting,Windows-Identity-Foundation,Server-Media-Foundation,Xps-Viewer -Source D:\Sources\sxs

This process took no more than a few minutes to complete.  After a quick reboot the configuration is completed.  After logging on I restarted the Preparation Tool and it completed without error.