STUDY: MAC ADDRESS

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🔍 MAC Address Explained: Uniqueness, Structure & Privacy

We must correct a common misconception: a MAC address is designed to be globally unique, but it is NOT absolutely guaranteed that no duplicates exist in the world. Here's the accurate technical breakdown.

✅ What Is a MAC Address?

MAC (Media Access Control) Address is:

• A hardware identifier
• Assigned to a network interface (Wi-Fi, Ethernet, etc.)
• Used at Layer 2 (Data Link Layer) of the OSI model
• Typically 48 bits long

Example format:

00:1A:2B:3C:4D:5E 00-1A-2B-3C-4D-5E

✅ Structure of a MAC Address

A standard MAC address is 48 bits (6 bytes).

It is divided into two parts:

[ First 3 bytes ]

OUI (Vendor)

+

[ Last 3 bytes ]

Device ID

1️⃣ First Half — OUI (Organizationally Unique Identifier)

• Assigned by IEEE
• Identifies the manufacturer (e.g., Apple, Intel, Samsung)
• Each manufacturer gets a unique block of prefixes

2️⃣ Second Half — Unique Device Identifier

• Assigned by the manufacturer
• Meant to uniquely identify each device they produce

Total possible combinations:

2⁴⁸ = 281,474,976,710,656

That's over 281 trillion possible MAC addresses.

✅ Why People Say “No Two Are The Same”

In theory:

• Each manufacturer has a unique OUI
• Each device under that OUI gets a unique number

So practically speaking: The chance of accidental duplication is extremely low.

That is why people say: “Every device in the world has a unique MAC address.”

⚠ But Important Reality Check

MAC addresses are:

• Not cryptographically guaranteed unique
• Not centrally tracked per device globally
• Can be manually changed (MAC spoofing)
• Can be duplicated by manufacturer error
• Often randomized in modern devices (privacy feature)

So: It is designed for uniqueness, but not mathematically impossible to duplicate.

✅ What Is MAC Address Used For?

Inside your local network:

• Router uses MAC address to identify devices
• Switch uses MAC address to forward frames
• ARP protocol maps IP ↔ MAC

Important: MAC address works only:

Inside the same local network (LAN)

It does NOT travel across the public internet.

✅ MAC vs IP — Clear Comparison

Feature	MAC Address	IP Address
Layer	Layer 2 (Data Link)	Layer 3 (Network)
Scope	Local network only	Local + Internet
Assigned by	Manufacturer	Router / ISP
Can change?	Yes (spoofable)	Yes
Visible to websites?	❌ No	✅ Public IP only

✅ Can Websites See Your MAC Address?

No.

Web browsers do NOT expose:

• Your MAC address
• Other devices' MAC addresses

Because:

• MAC works at a lower networking layer
• It is not included in HTTP requests
• Routers strip MAC information before traffic reaches internet

So TikTok, Blogger, or any website: ❌ Cannot see your MAC address ❌ Cannot access hardware-level identity ❌ Cannot scan MAC addresses through browser JavaScript

✅ Why Modern Devices Randomize MAC

New phones and laptops often use MAC address randomization when scanning WiFi networks.

Why? To prevent:

• Tracking by physical location
• Device fingerprinting in public WiFi

So MAC is no longer even permanently fixed in many cases.

✅ Final Corrected Statement

Instead of saying:

“MAC address is a physical hardware identifier where no same number ever exists in the world.”

The technically correct statement is:

A MAC address is a hardware-level network identifier designed to be globally unique by IEEE assignment rules, but duplication is theoretically possible, and modern devices may randomize or spoof MAC addresses for privacy.

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✅ MAC address clarified — accurate technical explanation + working TikTok embed

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