Originally posted on: http://geekswithblogs.net/rohancragg/archive/2013/07/24/configuring-sql-server-express-edition-for-remote-access.aspx

I wanted to access SQL Express on my local machine from within a Client Hyper=V virtual machine on the same Domain.

This article got me most of the way there:

http://akawn.com/blog/2012/01/configuring-sql-server-2008-r2-express-edition-for-remote-access/

But it was a bit out of date.

My steps were:

1. Enable TCP/IP Protocol in SNAC
   
2. Restart SQL Server
3. Configure (Windows 8) Firewall to allow all Inbound for sqlservr.exe
   
   
   

Footnote:

I thought this might be relevant (nice to be able to script it):

http://support.microsoft.com/kb/968872/en-us

But the problem is that this is for fixed ports and not compatible with the (default) Dynamic Ports settings above.