RPC and RPC Out option on a SQL Server linked-server

The first RPC setting is mainly for a legacy feature called Remote Server, which is documented here. http://msdn.microsoft.com/en-us/library/ms190187.aspx

You probably will not be using remote servers in SQL Server 2005 -SQL Server 2014 versions.

If you do happen to use “remote servers”, the RPC setting enables a certain security feature.

Sources:

What is the RPC and RPC Out option on a SQL Server linked-server?