Defensible Security Architectures: Network Environment

Name: Defensible Security Architectures: Network Environment
Author: James Youngblood

Learn how network topologies, network filtration devices, and servers all affect security architectures

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Course: On-Demand

Hello, my name is James Youngblood, and in this module of Defensible Security Architectures, we're gonna talk about network environments. And specifically in this lesson, I wanna talk to you about physical and logical network topologies and why they matter. So to begin with, when we're talking about network topologies, we're talking about the way a network is actually set up. Network topologies describe the layout of the network, both physically, and this is the actual placement of the devices and the wiring; and also logically, the way that data actually passes through a network. Now, the layout of our network can have a huge impact on our network security. To begin with, let's talk about point-to-point networks. In a point-to-point network, it connects two devices directly to each other. A point-to-point network is a very secure network in the fact there are only two devices that can see the network traffic. This makes it pretty much impossible for a hacker to actually tap into this connection because it's typically a physical wire that is directly connecting these devices to each other. Now, in practicality, we see point-to-point networks set up between two routers. And many times these point-to-point networks are actually set up as a subnetwork of a much larger network. Now, I said that our network topologies can have an effect on the security of our network, and the bus topology is a very good example of this. You're going to hear a lot of IT people say that bus topologies are a thing of the past. And when we are talking about physical layouts, they are correct. But the way that many of our networks today are set up and they operate, they actually incorporate logical bus topology in them, and you'll see that shortly. But in a bus topology, I should state the bus topology, all the nodes, and nodes are the devices on the network, all the nodes and switches are connected to only one single cable, which can be also known as the backbone or the bus. Now, in a physical bus typology, the nodes are connected in half duplex mode. And let me explain that. So when we're talking about half duplex versus full duplex, in a full duplex mode, a computer can send and receive data at the same time. In half duplex, it can either send data or it can receive data but it can't do both at the same time. But each node is gonna be set up in half duplex mode and it's gonna be assigned a number because all the devices share a single cable. We have to use half duplex mode, because if we don't, that means we're gonna have devices both sending and trying to receive data at the same time and you're gonna have what's called packet collisions. This is where two devices are trying to transmit at the same time, and those packets will actually hit each other and cancel out, so that data ends up getting lost. Now the security issue with bus typology comes in the fact that all packets go to all nodes, rather they're the intended recipient or not. Whenever we are on a bus topology, every transmission is known as a broadcast, and a broadcast goes to every device instead of it being a unicast, which is for a specific device. So because all of these communications are done as a broadcast, basically it's going to increase the chance that an intruder can intercept those packets and use them to steal information. Moving onto the next one is the ring topology. And in a ring topology, each computer is connected to two computers. And the way that data flows in this network is kind of unique. Data only flows in one direction, and that's clockwise. So when a packet is sent from a computer, it travels in a clockwise motion until it reaches the computer that is the destination. If any computer is removed from the ring, the connection is broken and no data can pass across the network. Security is an issue with the ring topology as well, and it's kinda obvious as the reason why. In order for a packet to reach its intended destination, it has to be passed from computer to computer until it reaches its destination. So that means any computer between the sender and the recipient, they have the potential to intercept that signal and steal that information. So while a ring typology actually increases the bandwidth, an action increases the efficiency of our network over a bus typology, it doesn't help us because the fact that we can still have our data intercepted and stolen. Of all the topologies that we're gonna talk about, the star topology is the one that you probably need to remember the most. Star topology is the most commonly used network topology in today's networks. The star topology has a central connection device in the center that all other nodes connect to. The star topology is not the most secure topology, but it is one of the most efficient topologies. I do want to say, however, we do see an increase in security over the ring topology and the bus topology. Now, the tree topology is probably what you will see in most large businesses. And the best way to look at a tree topology is to think of it as several star and bus topologies connected together. In essence, there's a single bus line, but there will also be several star topologies that connect to this single bus line. It's also not uncommon to find a couple of point-to-point connections on this as well. The security concern with this type of network though is that if a hacker's able to tap into the backbone cable, he will be able to monitor the traffic from all the different star networks. So that's still an issue we're gonna be dealing with here. When discussing mesh networks, which is our next topology, I need to make sure I differentiate something here. There is a big difference between a wired mesh network and a wireless mesh network. The main thing to understand about a mesh network is that it has a direct connection to every other device on the network. And this is why I said we have to differentiate between the two, because when we're dealing with a wired mesh network, we are dealing with a network that has a physical connection to every other device in the network. In other words, if I have four computers on my network, every computer will have three wires coming out of the back that connects this computer to the other three computers. There is a dedicated wire that connects me to each node in my network. Now, wired mesh networks are usually very small because of this fact. If I have seven computers on my network, that means I need six wires coming out of the back of each computer. Well, you can already see that starts to get pretty complicated. Mesh networks do not have any central control. They're made up of several point-to-point networks. In essence, every single wire that comes out is a point-to-point network. Wireless mesh networks are similar, but there are no wires involved, just a wireless signal. So each computer will actually establish a wireless communication between each other computer on the network. Understand when we're talking about these different types of networks and we're talking about the security for our networks, you're starting to understand that there's not a single network out there that is 100% secure. What we want to do though, is we want to recognize the fact that there are some networks that are more secure than others, and some network topologies that are much more secure than others. Thank you for watching this lesson on Defensible Security Architecture. And join me in my next one as I talk about NEDS, NIPS and other data filtration devices.

Intermediate Provider : James Youngblood 3 Lessons · 21m in Arabic, German, English, Spanish, French, Portuguese, Chinese

Course Description

What exactly is a network? To understand defensible security architecture, you first need to understand what a network actually is. Terms like bus, star, tree, ring, and mesh may not mean much to most people, but they are incredibly significant to network administrators and security analysts. These terms are used to describe the topologies of networks or, in other words, the way a network is structured. They explain how the wiring for a network is put into place, and how data is moved throughout a network. Network topologies are crucial for both the efficiency and the security of a network. We will discuss how to use security equipment such as next generation firewalls, NIDS, NIPS, and servers, as they are all equally important to the security of our network. These devices create the rules and policies used to manage communication inside a network, and any communication from a network to the outside world.

In these lessons, you will learn how a network environment affects its security. We will explore how the physical and logical layouts of a network can have a major impact on its security. We will discuss the ways certain topologies can actually make our network more difficult to secure. Finally, you will learn how servers and security devices, such as firewalls, work to secure our networks.

What You'll Learn

Describe the star network topology and identify the different parts of a tree topology
Explain the security issues that come with a bus topology
Differentiate between NIDS and NIPS devices and other data filtration equipment
Explain the role servers play in defensible security architecture
Recognize how physical and logical network layouts affect a network's security
Understand how security equipment such as next generation firewalls works to secure networks

Key Takeaways

Network topologies (bus, star, tree, ring, and mesh) describe the way a network is structured, including how its wiring is put into place and how data moves through it.
Network topologies are crucial for both the efficiency and the security of a network, and certain topologies can make a network more difficult to secure.
Security devices such as next generation firewalls, NIDS, NIPS, and servers create the rules and policies that manage communication inside a network and between a network and the outside world.
Both the physical and logical layouts of a network can have a major impact on its security.
Servers and security devices like firewalls work together to secure networks.

Frequently Asked Questions

What does this course cover?

The course explains what a network is, covers network topologies such as bus, star, tree, ring, and mesh, and shows how the physical and logical layouts of a network affect its security. It also covers security equipment including next generation firewalls, NIDS, NIPS, and servers, and how these devices secure networks.

Who is this course for?

The data describes terms used by network administrators and security analysts, and the course teaches defensible security architecture for network environments, making it relevant to those working on network security.

What skills will I gain from this course?

The course is associated with skills including Computer Network Defense, IT Security Architecture, Network Security, Network Security Design, Security Patterns, and Security Certified Network Architect.

What topics are taught in the lessons?

The lessons cover Physical and Logical Network Topologies and Why They Matter; NIDS, NIPS, and Other Data Filtration Devices; and The Role of Servers in Security Architecture.

What will I be able to do after completing this course?

You will be able to describe the star network topology, explain the role servers have in defensible security, identify the different parts of a tree topology, explain the security issues with a bus topology, and describe the differences between a NIDS and a NIPS device.