ICS-SCADA Exam Dumps : ICS/SCADA Cyber Security Exam

Ingress filtering is a method used in network security to ensure that incoming packets are allowed or blocked based on a set of security rules.

This type of filtering is often implemented at the boundaries of networks to prevent unwanted or harmful traffic from entering a more secure internal network.

The term "ingress" refers to traffic that is entering a network boundary, whereas "egress" refers to traffic exiting a network.

References

Cisco Networking Academy Program: Network Security.

"Understanding Ingress and Egress Filtering," Network Security Guidelines, TechNet.

The Modbus protocol was developed by Modicon, now a brand of Schneider Electric.

It was originally designed in 1979 for use with its programmable logic controllers (PLCs) in industrial applications.

Modbus is a serial communications protocol that has become a de facto standard communication protocol and is now commonly used to connect industrial electronic devices. The main reasons for its use are its simplicity and the fact that it is open-source, which allows manufacturers to build their own implementations of the standard.

References

"Modbus Protocol Reference Guide," Modicon, Inc., 1979.

"A Guide to the Modbus Protocol," Schneider Electric.

The first generation of ICS/SCADA systems is considered monolithic, primarily characterized by standalone systems that had no external communications or connectivity with other systems. These systems were typically fully self-contained, with all components hard-wired together, and operations were managed without any networked interaction.References:

U.S. Department of Homeland Security, "Recommended Practice: Improving Industrial Control System Cybersecurity with Defense-in-Depth Strategies".