An Oracle instance can run in restricted mode, which allows access only to users who have the RESTRICTED SESSION system privilege. To connect to an instance running in restricted mode, add the UR = A clause to the CONNECT_DATA parameter of the tnsnames.ora file as shown.


...
(CONNECT_DATA=
     (SERVICE_NAME = acct.us.yourcompany.com)
     (UR = A)
 )
...