Tra Cứu Địa Chỉ MAC

Structure

A MAC address is 48 bits (6 bytes). The first 3 bytes are the OUI (Organizationally Unique Identifier) assigned to the manufacturer. The last 3 bytes are the device-specific NIC identifier.

Formats accepted

• 00:1A:2B:3C:4D:5E — colon-separated
• 00-1A-2B-3C-4D-5E — dash-separated
• 001A.2B3C.4D5E — Cisco dot notation
• 001A2B3C4D5E — raw hex

Special types

• Multicast — LSB of first byte is 1
• Locally Administered — 2nd LSB of first byte is 1 (VMs, VPNs)
• Broadcast — FF:FF:FF:FF:FF:FF

Privacy note

Modern devices use randomized MAC addresses for Wi-Fi scans. These will show as "Locally Administered" and won't match a real vendor.