exec sp_addlinkedserver 'sql2','','SQLOLEDB','172.16.8.121'

exec sp_droplinkedsrvlogin 'sql2,null

exec sp_addlinkedsrvlogin 'sql2','false','currentsqlloginuser','remoteloginuser','remoteloginpassword'

select * from sql2.db.dbo.tbl

...

exec sp_dropserver 'sql2','droplogins'