Cisco Certified Internetwork Expert (CCIE) Practice Test

In which instance is MAB considered effective?

1. When devices do not support 802.1x

2. Only in wireless networks

3. When both Layer 2 and Layer 3 are compromised

4. For devices under heavy load

The correct answer is: When devices do not support 802.1x

MAB, or MAC Authentication Bypass, is particularly effective when devices do not support 802.1X authentication. This scenario is common in situations involving legacy devices such as printers, IP phones, and some IoT devices that lack the capability to participate in 802.1X protocols. In these cases, MAB allows for the identification and authentication of devices based on their MAC addresses, enabling network access without requiring the device to support the more sophisticated authentication methods like 802.1X. The implementation of MAB provides a way to still secure the network while accommodating devices that may not have the necessary functionality for traditional authentication methods. By ensuring that authorized MAC addresses are permitted access, MAB can help maintain a level of security on the network, even when full 802.1X capabilities are not present. In contrast, the other scenarios do not align with the primary function or effectiveness of MAB. For example, MAB is not limited to wireless networks; it is applicable in wired scenarios as well. Additionally, addressing security breaches at Layer 2 and Layer 3 requires broader measures beyond what MAB offers, and heavy load conditions on devices are not a factor that enhances the effectiveness of MAC Authentication Bypass.