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Which of the following is a key feature of switch port security in a network?

• Limiting the number of MAC addresses that can be learned on a port.
• Blocking all unknown devices from accessing the network.
• Assigning IP addresses dynamically to connected devices.
• Prioritizing network traffic based on the type of data.

Switch port security is a crucial aspect of network management that helps protect the network from unauthorized access and potential threats. It involves various configurations and policies to control and monitor devices connected to switch ports. Let’s break down each option to understand its relevance to switch port security.

Option 1: Limiting the number of MAC addresses that can be learned on a port.

Explanation: This is a core feature of switch port security. By limiting the number of MAC addresses that a switch port can learn, network administrators can prevent unauthorized devices from connecting to the network. Once the limit is reached, the switch port can be configured to take specific actions such as shutting down, dropping packets from unknown MAC addresses, or generating an alert. This feature helps in mitigating MAC flooding attacks where an attacker attempts to overwhelm the switch’s MAC address table with fake addresses.

• Example Scenario: If a switch port is configured to allow only two MAC addresses, and a third device tries to connect, the switch port may shut down, preventing unauthorized access.

Option 2: Blocking all unknown devices from accessing the network.

Explanation: While this sounds like an effective security measure, it is not typically a feature of switch port security. Switch port security focuses on managing and restricting MAC addresses rather than blocking unknown devices entirely. Completely blocking unknown devices can lead to network management challenges, especially in dynamic environments where devices frequently connect and disconnect.

• Example Scenario: A network administrator can use switch port security to block devices with unrecognized MAC addresses, but this is a more granular approach than simply blocking all unknown devices.

Option 3: Assigning IP addresses dynamically to connected devices.

Explanation: This function is related to DHCP (Dynamic Host Configuration Protocol) and is not a feature of switch port security. Switch port security deals with MAC addresses and the physical security of the switch ports. DHCP assigns IP addresses to devices, which operates at a different layer of network management.

• Example Scenario: When a device connects to the network, DHCP assigns it an IP address. This process is independent of switch port security, which does not manage IP address assignment.

Option 4: Prioritizing network traffic based on the type of data.

Explanation: This feature is related to Quality of Service (QoS), which prioritizes different types of network traffic to ensure that critical services have the necessary bandwidth. QoS operates at a higher level of network management and is not a component of switch port security. Switch port security is focused on controlling access based on MAC addresses.

• Example Scenario: QoS can be used to prioritize VoIP traffic over regular data traffic to ensure clear voice communication, but this is separate from the security mechanisms provided by switch port security.

Detailed Explanation of the Correct Answer

The correct answer is Option 1: Limiting the number of MAC addresses that can be learned on a port.

Why Limiting MAC Addresses is Crucial:

1. Security Against MAC Flooding:
   • Attackers may use MAC flooding to exhaust the memory of a switch’s MAC address table, forcing it to broadcast traffic to all ports. Limiting MAC addresses helps prevent this type of attack.
2. Control Over Device Access:
   • By restricting the number of devices that can connect to a port, administrators gain control over which devices can access the network. This reduces the risk of unauthorized access and ensures that only trusted devices are allowed.
3. Alerting and Actions:
   • When the limit is exceeded, the switch can be configured to alert administrators, drop traffic from the new MAC addresses, or shut down the port. These actions help in quickly responding to potential security incidents.
4. Granular Security:
   • This feature provides a granular approach to network security, allowing administrators to fine-tune access policies on a per-port basis.

Conclusion:

Switch port security plays a vital role in protecting a network from unauthorized access and potential attacks. Among the various features, limiting the number of MAC addresses that can be learned on a port is fundamental. It helps prevent MAC flooding, controls device access, and enables swift responses to security incidents. Understanding and implementing this feature is essential for maintaining a secure and efficient network environment.