This bitmask selects which of the 16 NNCLI command privilege levels (level0 through level15) are subject to TACACS+ command authorization, defaulting to none selected. An admin sets bits for the specific privilege levels they want checked against the TACACS+ server on every command, letting them apply command authorization only to higher, more sensitive privilege levels while leaving lower levels unchecked. For example, an admin might set only the level6 and level15 bits so that only commands run at those two privilege tiers get authorized by TACACS+, while commands at other levels are not checked.