Does Port Security Let It On?

About this interactive

Every network interface card has a MAC address burned in by its maker, and a LAN uses it to deliver frames. Port security limits who can plug into a switch port by that address. Static port security is set by hand: the port accepts the address entered for it and nothing else. It is the more secure option and the harder one to manage. Dynamic port security learns the first address it sees. It can keep that address until someone resets the port, or forget it after a time limit so another machine can use the port, which is easier to manage and less secure. A port can also limit how many addresses it allows at once: one or two per port lets ordinary devices in but stops someone from plugging in a switch full of devices. The weakness is the address itself. A MAC address is visible to anyone on the LAN or in range of the wireless network, and it is easy to change. A device that copies an allowed address gets on. Wireless MAC filtering works the same way and has the same weakness.

What you'll learn

Predict whether a device gets onto a port protected by static or dynamic port security, including a learned address kept until reset or dropped after a time limit
Predict the effect of a limit on the number of MAC addresses per port, and recognize that a spoofed MAC address gets past port security

Aligned to

CompTIA Security+

3.2 Given a scenario, apply security principles to secure enterprise infrastructure.

Key terms

Port Security: A Cisco switch feature that restricts which devices can connect to a port by limiting the number of allowed MAC addresses or requiring specific MAC addresses to be present. When a violation occurs, the port can be configured to shut down, restrict traffic, or send an alert.
Media Access Control: A sublayer of the Data Link layer that controls how devices on a network gain access to a medium and transmit data.
Spoofing: An attack where an adversary impersonates a trusted entity by falsifying data such as an IP address or email address.
Switch: A network device that connects devices within a LAN and forwards traffic based on MAC addresses.

Topics

Interactive Streak Sort

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