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Depth resolution: MAC address and device identification rationale

MAC Address (Media Access Control Address) is the only hardware identifier given to each card upon exit. It's in the... The second layer of the OSI model (data link layer) ensures that the package within the LAN is accurately delivered to the target equipment. I understand, MAC. The structure of the address is not only useful for network management but also an important element of security audits.

Structure of MAC address: OUI and NC

A standard MAC address consists of 48-bit binary, usually expressed in 6 hexadecimals. It is divided into two parts:

Top 24 bits: Organisationally United Identifier. This part is by IEE. Uniformly distributed to equipment manufacturers. Pass this three. A byte, we can know exactly whether the device was made by Wao, Apple, Cisco or Intel.
After 24 bits (NIC): Network interface controller (Network Interface) Controller）。 This part is allocated by the manufacturer itself, ensuring the uniqueness of each card.

How can specific cybersecurity and management issues be addressed?

Scenario I: Identification of unknown equipment in local area networks. When you find a MAC address you have never seen in the router backstage, check through this tool OUI, if the results are “Espressif”, it is likely to be a smart-house plug or a network module; If it's Apple, it could be family. iPhone。 This helps to rapidly remove potential wipers.

Scenario 2: Compatibility of the screening network. Some old-model webcards may have driver compatibility in a given switch environment. Through MAC The search for the identification of the manufacturer and the batches can provide a key clue to the problem of positioning.

Randomize about MAC addresses

Note: To protect privacy, modern smartphones (e.g. iOS 14+ and Android 10+) are scanning Wi-Fi When you connect to a public network, you generate a "random MAC address". In this case, MAC The address prefix is no longer the true physical manufacturer and the tool may not be able to identify its true source. It's to prevent third parties from passing through. MAC addresses track your movements.