Understanding MAC Address Configuration for Port Security in Cisco Switches

How many MAC addresses can be configured by default for port security on a switch port?

• A. 1
• B. 5
• C. 10
• D. 1024

Answer: (A)

In Cisco switches, the default configuration for port security allows for the configuration of a single MAC address per port. This means that a switch port will only permit that one specific MAC address to send frames through that port. This feature is intended to enhance network security by limiting access to authorized devices. If a device with a different MAC address tries to send data through that port, the switch can take predefined actions such as shutting down the port, dropping the traffic, or sending alerts, depending on the configured security settings. While it is possible to change this default setting to allow more MAC addresses – such as 5, 10, or even up to 1024 – the default behavior is to restrict access solely to one MAC address to ensure a higher level of security on that port right from the start.

When it comes to securing a network, every little detail counts. Now, let’s talk about something that might not be top of mind but plays a crucial role: MAC address configuration for port security on switches. Here’s the scoop—you can configure just one MAC address by default for port security on Cisco switches. Yup, you heard it right, just one!

This single MAC address is essential for granting access to a specific device on the network. Why, you ask? Well, the primary goal of this approach is to enhance security. Imagine your network as a prestigious club—only the VIP (Very Important Protocol) gets in. If any device tries to sneak in with a different MAC address, the switch has a few tricks up its sleeve. It can either shut down the port, drop the unauthorized traffic, or even send out alerts! Doesn’t that sound like a solid plan?

Now, let me explain a bit more about how this works. The Cisco switch's default behavior is designed to limit access. Think of it this way: if your network were a gated community, only the residents (those authorized devices) would have access. By allowing only one MAC address to communicate through that port, we maintain strict control over who gets in. This means your network is less susceptible to unauthorized access and security threats.

However, there’s a twist! Should you need to allow a few more friends in (or devices, in our case), you can tweak this default configuration. Switches can be set up to allow additional MAC addresses—like 5, 10, or even up to an eye-popping 1024! Just remember, each added MAC address increases the potential for risk, so make sure you really need that extra access. Sometimes, more isn’t necessarily better when it comes to security.

Now, I can hear some of you saying, “But why should I restrict access at all?” Great question! By limiting MAC addresses, you mitigate the chance of unauthorized devices flooding your network with unwanted traffic or even orchestrating attacks. It’s like keeping the riff-raff out while letting in only the cool crowd—even if they sometimes need more than one or two of their buddies to hang out.

In conclusion, understanding how many MAC addresses you can configure by default for port security isn’t just a trivial detail on your study path for the Cisco Certified Network Professional Practice Test—it’s a crucial aspect of network security. It sets the foundation for ensuring your network remains secure and only accessible to those who are intended to be there. Keep this concept in mind as you prepare, and you’re well on your way to mastering not only the test but also the skills you’ll need in real-world scenarios. Happy studying!