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Network Infrastructure.

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Network infrastructure is the backbone

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of any modern organization.

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It comprises the hardware, software, services,

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and facilities required to support, manage,

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and operate an enterprise network.

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A critical aspect of network infrastructure

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is the separation of network components,

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which can be achieved either physically or logically.

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In this lesson, we'll dive into these two methods.

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First, Physical Separation.

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Physical separation often referred to as Air Gapping,

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is a security measure employed

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to protect sensitive information.

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An Air Gap system is isolated from other networks,

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both local and internet.

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By physically disconnecting it from those networks,

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this isolation is achieved

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by removing all direct or indirect connections,

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including Wi-Fi, Bluetooth,

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and other wireless connections.

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An example of an Air Gap system

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is a military or government network

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holding classified information.

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These networks are kept physically separate

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from the public internet

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to prevent unauthorized access and cyber-attacks.

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Another example is an industrial control system

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or ICS system

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used in critical infrastructure,

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like power plants or water treatment facilities.

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These systems are often Air-Gapped

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to prevent potential cyber, physical attacks

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that could lead to real-world damage.

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However, Air Gap systems are not infallible.

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Sophisticated attacks such as Stuxnet

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have demonstrated that Air Gap systems can be compromised.

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Despite this, physical separation

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remains one of the most secure methods

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of protecting sensitive information,

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provided that strict physical security measures

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are in place.

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Logical separation, on the other hand,

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whilst creating boundaries within a network

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that restrict access to certain areas

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this is typically achieved through the use of firewalls,

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virtual local area networks or VLANs,

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and other network devices that can control traffic

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based on rules and policies.

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A common example of logical separation

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is the use of VLANs in a corporate network.

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VLANs can segregate network traffic

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ensuring that data from one department,

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such as human resources,

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cannot be accessed by another department like marketing,

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despite being on the same physical network.

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This separation helps to improve security,

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manage network traffic, and reduce congestion.

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Another example is the use of firewalls

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to create a screen subnet network,

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there's a logical subnetwork

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that contains the organization's external-facing services,

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separating them from the internal network.

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This prevents an attacker

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who has gained access to the screen subnet

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from easily moving to the internal network.

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While logical separation

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provides a high degree of flexibility

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and is easier to implement than physical separation,

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it is not as secure.

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If not properly configured,

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firewalls and other network devices can be exploited,

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allowing unauthorized access

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to restricted areas of the network.

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So remember, both physical and logical separation

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play crucial roles in network infrastructure and security.

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Physical separation or Air Gapping

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provides a high level of security

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by completely isolating a system from other networks.

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Logical separation,

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while not as secure as physical separation,

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offers more flexibility and is easier to implement.