The built-in SQL Server function OPENROWSET() provides a way to access remote data from an OLE DB data source. It can be used with the BULK rowset provider to read data from a file without loading the data into a target table. This post will show the basics to get started with OPENROWSET(), the BULK rowset provider, and text files of fixed-width data fields.
For permanent connections, look into linked servers. But for one-off things, OPENROWSET works fine.