127.0.0.1

I installed sqlserver 2008 r2 developer and used default instance. I also have a SQLEXPRESS instance which works

I can connect to the default connection using . or (local) directly without using instance name.

SQLEXPRESS also runs with 127.0.0.1\SQLEXPRESS but default instance does not run with 127.0.0.1

I configured the TCP/IP same as the previous SQLEXPRESS instance as below. Left picture is for named SQLEXPRESS and right is for default instance.

IPAll settings for default is

TCP dynamic Ports 0

TCP Port blank