However, instead of changing the UID and user pro®le for each user on each system, administrators can use the QSYCHGID API (application programming interface). This new API can be called from AS/400 command lines, C programs, COBOL programs, and through other interfaces as well. This function can change the UIDs and GIDs of both system-provided pro®les and regular user pro®les. To use this command, an administrator must include the following entries:

1.A ten-character pro®le name. This is the name of the user or system pro®le that is to be changed. An example of such a pro®le name would be BILL or QUSER.

2.A UID value. This is the new value for the UID of the user or system pro®le that you speci®ed. A value of '-1' indicates that the UID will not change.

3.A GID value. This is the new value for the GID of the user or system pro®le that you speci®ed. A value of '-1' indicates that the GID will not change. A value of '0' indicates that the GID will be removed from the user or system pro®le.

4.A pointer to an error code structure. This pointer cannot be provided from a command line, although it works through a programming interface. If a value of '0' is speci®ed for this parameter, the user will be sent exceptions if the command fails to function.

To operate QSYCHGID, an administrator must ®rst end all jobs that are currently running under the system or user pro®le name. If this is a system-provided pro®le, AS/400 may require an entrance into ªrestricted state,º meaning that all interactive, batch, daemon, and request jobs are ended. You can establish a ªrestricted stateº with the ENDSBS command. All that should be left operating is the system console, the console that is directly attached to AS/400.

QSYCHGID will update a user or system pro®le with the appropriate UID value, as well as all objects that a user or system owns. If the objects that are owned by a user or system fail to be updated, then you should use the Reclaim Storage (RCLSTG) command to reclaim any possible lost objects.

Note: QSYCHGID will always fail if a UID number is chosen that is already allocated to an existing user or system pro®le. No UID value can belong to more than a single pro®le.

Note: UIDs and GIDs are not mutually exclusive. That is, a UID value of 500 and a GID value of 500 do not signify the same pro®le.

Securely Exporting File Systems

When namespace administrators export ®le systems, these are the rules they should consider:

1.Use an exact list of clients who have access to mount and otherwise work with the ®le systems that are exported. This will keep sensitive information out of the reach of clients that are not listed with the ACCESS option of the OPTIONS parameter of the CHGNFSEXP command.

2.Use QNFSANON extremely carefully when allowing anonymous UIDs access to exported ®le systems. When coupled with the ROOT parameter, it can give unknown (anonymous) users access to your namespace.

3.Always exclude access to the /etc/exports ®le. Donot export this ®le. A user may ®nd a way to access this ®le and make data available to other users that would otherwise be safely guarded.

When administrators export ®le systems, they shouldnever do the following:

Chapter 9. Network File System Security Considerations 87

Page 104 Page 106
Page 105
Image 105
IBM AS/400E manual Securely Exporting File Systems
Page 104 Page 106

AS/400E specifications

The IBM AS/400E, now more commonly known as IBM i, is a robust and versatile midrange server that has been designed to provide a comprehensive computing solution for businesses of all sizes. First introduced in the late 1980s, the AS/400 series has undergone multiple enhancements and rebranding, with the AS/400E being one of the notable iterations. This powerful platform is closely associated with IBM's commitment to reliability, scalability, and integrated business solutions.

One of the main features of the AS/400E is its highly integrated architecture that combines hardware and software into a cohesive system. This integration allows for seamless operations, reducing the complexity typically associated with managing disparate systems. The system is powered by IBM's proprietary OS/400 operating system, which has evolved into IBM i, featuring advanced capabilities like object-oriented programming, integrated database management, and security features that are essential for enterprise environments.

A key characteristic of the AS/400E is its robust database support, primarily through the use of DB2 for i. This integrated database management system enables efficient data handling and retrieval, facilitating real-time business analytics and reporting. Furthermore, the platform supports a variety of programming languages, including RPG, COBOL, and Java, making it flexible for developers who require diverse tools for application development.

The AS/400E is also known for its exceptional reliability and uptime, making it a preferred choice for critical business applications in industries such as finance, healthcare, and manufacturing. This reliability is backed by advanced error detection and correction mechanisms, as well as redundancy features that help prevent data loss and minimize downtime.

In terms of scalability, the AS/400E can effortlessly expand to accommodate growing business demands. Organizations can increase processing power by adding more resources without significant disruption. This scalability, combined with the system’s built-in virtualization capabilities, allows businesses to optimize resource usage and streamline operations.

Security is another defining feature of the AS/400E. The platform incorporates various layers of security measures, including user authentication, encryption, and comprehensive auditing capabilities, ensuring that sensitive business data is protected against unauthorized access.

Overall, the IBM AS/400E remains a powerful tool in the enterprise computing landscape, providing businesses with an integrated, reliable, and secure solution for their technological needs. Its enduring popularity is a testament to its capability to evolve with changing business requirements while maintaining its core attributes of high performance and stability.
Top Page Image Contents