To add to what djj55 suggested, if you connect to the default instance of SQL Server on 10.194.2.4 and run the following query you will see a list of linked servers:
SELECT * FROM sys.servers
The server name you specify in the four-part naming has to be one of the names listed in the name column. When you add a linked server, you can name it to what makes sense to you (although naming it to an IP address might not be a great idea - it might cause more confusion than clarity).