Oracle Database 10g and later allows SSL-authenticated external users and SSL-authenticated global users to coexist in the database. Previous releases had the restriction that all SSL users must be either global users or external users, depending on whether Oracle Internet Directory is being used or not for authenticating the users.
If you want a user to be able to connect to the database even when Oracle Internet Directory is not available, then the user should be configured as an external user. You can convert SSL-authenticated global users into SSL-authenticated external users by using the SSL external users conversion script.
For example:
extusrupgrade --dbconnectstring mymachine:1521:11gR2 --dbuser system --dbuserpassword manager -l user1,user2
The preceding example converts two global users into external users.