AS400 System Security Levels


Level 10: There is no user authentication, or resource protection. No password is required to sign on. This is no longer supported. (Discontinued in OS/400 Version 4, Release 2)

Level 20: Password - User authentication through user profile and password checking; no resource protection. 


(Resource security means object security that provides protection for system objects like programs, files, and libraries, and the data within these objects.)

Level 30: Password and Resource - User authentication and resource protection. Users require authority to access objects.

Level 40: Password, Resource and Operating System Integrity - User authentication, resource protection, and machine interface protection.

Level 50: Password, Resource and enhanced Operating System Integrity - User authentication, resource protection,and machine interface protection. Security level 50 is intended for AS/400 systems with high security requirements and to meet C2 security requirements.


The iSeries are shipped with a default setting of 40. The system can only be set to one level for all users at any given time. The recommended setting for a secure iSeries machine is 40. This level of security is highly recommended for those locations that have complex processing that includes non-IBM system interfaces, network connectivity and processing of external tapes. One may think using 50 would be even better because it would be even more secure. This statement is true, however, there is a 5 to 15 percent performance decrease in going from level 40 to 50 and also a level of 40 provides an adequate level of security for typical companies.