Actually , you don't even need to run sp_addLinkedServer. What you need to do is

1) your SQL server must run under the account which must have access right to the active directory.

2) you must login to active directory to run this query.

SELECT*

FROM OPENROWSET('ADSDSOObject', 'adsdatasource;',

'SELECT mail, displayName,givenname,distinguishedName, SAMAccountName, CN

FROM ''LDAP://ServerName/cn=users, DC=DOMAINName, DC=com'' ')