Create the alias with cliconfg.exe

Option 2: Create the alias with cliconfg.exe
Log into the Application and/or front-end Web servers
Got to Start > cliconfg.exe (Note: it’s c-l-i-c-o-n-f-g-dot-e-x-e)

Then click on “Alias”:

If you already have an alias set up, it will show up there. Otherwise…
Click “Add”

Specify the port number and give it a name. That’s it!
Test your SQL Alias:
To test your SQL alias, create a Microsoft Data Link (udl) file on your desktop:

From your desktop, right click on the desktop and choose New > Text file
A new file named New Text Document.txt appears in the directory.
Rename this file to “TestDBConnection.udl”, removing all spaces. Be sure to change its file extension to .udl.
Open the file and, under Connection, type either the SQL server name or, if you are testing an SQL alias, the alias name.
Under 2, chose “Windows Authenticated security”
Click “refresh”
If the connection was successful, list of databases should appear in the dropdown menu under #3.
I have a separate blog post that covers the same steps for creating a udl file here. http://smallcitydesign.com/how-to-test-a-database-connection-from-an-application-server/