What Is a MAC Address?

A MAC (Media Access Control) address serves as a unique hardware identifier assigned to a network interface controller (NIC). It operates at the data link layer of the OSI model and is essential for local network communication. Unlike IP addresses, which can change dynamically, MAC addresess are typically hardcoded into the device’s firmware or stored in non-volatile memory like EEPROM.

Viewing Your Device’s MAC Address

On Windows

When connected via Ethernet, the displayed MAC corresponds to the wired NIC. For Wi-Fi connections:

• Windows PCs use the physical MAC address of the wireless adapter by default.
• Modern devices often enable MAC randomization for privacy.

To retrieve the MAC address:

Get-NetAdapter

Or use:

ipconfig /all

Alternatively, open System Information via Win + Q, navigate to Components > Network > Adapter, and locate the physical address field.

On Mobile Devices

Most smartphones display a randomized MAC address when connected to Wi-Fi networks — labeled as WLAN MAC in settings. This is a privacy feature introduced to prevent device tracking across networks.

Even after forgetting a network, the randomized MAC often remains unchanged. This suggests the system derives the randomized address using a deterministic algorithm based on the device’s original MAC and the network’s SSID — effectively a one-way mapping.

Some older devices lack this feature and always expose the true hardware MAC. To view both addresses on Android, check Settings > About Phone > Status > WLAN MAC — some manufacturers hide the original MAC behind the randomized one.

Discovering the Router’s MAC Address

From Windows

Use the ARP table to find the MAC address of your local gateway (typically the router):

arp -a 192.168.31.1

This returns the LAN-side MAC of the router — not the Wi-Fi interface’s MAC. If you run arp -a without an IP, you’ll see all known neighbors on the subnet, including your own assigned IP (e.g., 192.168.31.104).

From Android or Linux

Android lacks a built-in arp command, but provides ip neigh:

su
/system/bin/ip neigh show

While Termux offers arp, its root environment alters the PATH variable unpredictably when invoking su, making it unreliable for consistent output. Tools like MT Manager’s terminal provide a more stable environment for this task.

Modifying MAC Addresses on Routers

Router firmware often stores MAC addresses in the eeprom.bin file. Two common methods exist for modification:

1. Use a bootloader like Breed that offers built-in MAC editing.
2. Dierctly edit the eeprom.bin file using a hex editor.

Across multiple router models (including Xiaomi Redmi AX series), the following offsets are commonly observed:

• LAN MAC: Base address (x)
• WAN MAC: x + 1
• RF1 (2.4 GHz Wi-Fi): x + 2
• RF2 (5 GHz Wi-Fi): x + 3

The LAN MAC is the one visible via arp -a. The WAN MAC is typically printed on the router’s label. Modifying these correctly ensures proper network registration and avoids conflicts.

Understanding BSSID

While SSID (Service Set Identifier) is the human-readable network name, multiple access points may share the same SSID. To uniquely identify each radio, the BSSID (Basic Service Set Identifier) is used — which is simply the MAC address of the wireless radio interface.

For dual-band routers, RF1 and RF2 correspond to the 2.4 GHz and 5 GHz radios, respectively — each with its own BSSID.

Retrieving BSSID

On Windows

netsh wlan show interfaces

This shows the local adapter’s MAC — not the access point’s. The BSSID is listed under AP in the output.

On Linux (Ubuntu)

sudo apt install wireless-tools
iwconfig

Or use the newer iw tool:

sudo apt install iw
iw dev

On Android

Most stock tools don’t expose BSSID. Third-party apps like DevCheck can display it without root.

For manual inspection via Termux:

pkg install root-repo
pkg install iw
sudo iw dev wlan0 link

The output shows connect to <BSSID> — the MAC address of the connected access point. Note that Chinese SSIDs appear as escaped hex (e.g., \x7B\x65\x73\x74), which can be decoded back to UTF-8.

Hotspot MAC Addresses

When a device acts as a hotspot, it functions as a soft access point — and thus generates its own MAC addresses.

• Android Hotspot: Generates a new random MAC each time the hotspot is toggled, even with the same SSID.
• Windows Mobile Hotspot: Uses a fixed MAC derived from the host’s NIC, often randomized at first use — similar to Wi-Fi MAC randomization.

This behavior reflects different implementations of privacy policies: Android randomizes per-session for enhanced anonymity, while Windows maintains consistency for network stability.