MAC Address Converter

Explanation of the MAC Address Converter

The MAC Address Converter transforms Media Access Control (MAC) addresses into various standard formats and provides related information. MAC addresses are unique hardware identifiers for network interface controllers (NICs) at Layer 2.

Key information displayed includes:

  • Formatted Representations: MAC address in colon, hyphen, and dot notations.
  • OUI (Vendor): The Organizationally Unique Identifier, often indicating the manufacturer.
  • Administration Type: Universally (UAA) or Locally (LAA) Administered.
  • EUI-64 Conversion: If EUI-48 is input, its EUI-64 equivalent is shown.
  • IPv6 Link-Local Address: A potential IPv6 Link-Local address derived from the MAC.

A Guide to MAC Addresses, OUI Lookups, and IPv6 Link-Local Conversion

Instantly decode any MAC address to find its manufacturer, see its representation in different formats, and generate its corresponding IPv6 Link-Local address. This tool is essential for network engineers and IT professionals who need to identify devices on their network, troubleshoot Layer 2 connectivity, and work with both IPv4 and IPv6 environments. Understand the story behind the hardware address of any network device.

About the MAC Address Converter

The MAC Address Converter is a multi-function utility designed to parse and translate Media Access Control (MAC) addresses. A MAC address is a unique hardware identifier assigned to a Network Interface Controller (NIC) for communication on a physical network segment. Our tool takes a standard 48-bit (EUI-48) or 64-bit (EUI-64) MAC address and provides a comprehensive breakdown, including an OUI lookup to identify the hardware vendor, conversion between common notations (colon, hyphen, dot), and generation of the corresponding IPv6 Link-Local address, which is critical in modern networking.

How to Use the Converter and Interpret the Results

Our tool simplifies the analysis of any MAC address.

Using the Converter: A Step-by-Step Guide

  1. Enter a MAC Address: Type or paste the MAC address into the input field. The tool is flexible and accepts common formats with colons, hyphens, or dots as separators.
  2. Select the MAC Type: Choose EUI-48 (the standard for virtually all Ethernet and Wi-Fi devices) or EUI-64 from the dropdown.
  3. Click "Convert MAC": The tool will instantly process the address and display the results.

Interpreting the Results

  • Formatted Representations: See the address in the standard formats used by different systems: colon-separated (Linux/macOS), hyphen-separated (Windows), and dot-separated (Cisco).
  • OUI (Vendor): This field shows the manufacturer of the network hardware, based on the first half of the MAC address.
  • Administration Type: Indicates whether the address is universally unique (UAA, assigned by the manufacturer) or has been locally changed (LAA, or "spoofed").
  • EUI-64 Conversion: Shows the 64-bit version of the address, a key component in IPv6 autoconfiguration.
  • IPv6 Link-Local Address: Displays the automatically generated IPv6 address that the device would use for communication on its local network segment.

The Fundamentals of MAC Addressing

While IP addresses handle routing across the internet, MAC addresses are responsible for getting data to the correct device on a single, local network segment (like your home Wi-Fi or an office LAN). They operate at Layer 2 (the Data Link Layer) of the OSI model.

Structure of a MAC Address (EUI-48)

A standard 48-bit MAC address is divided into two main parts:

  • Organizationally Unique Identifier (OUI): The first 24 bits (6 hexadecimal digits) of the address. This prefix is assigned to a hardware manufacturer by the IEEE. Our tool's "OUI Lookup" feature uses a database to match this prefix to the company that made the device.
  • Network Interface Controller (NIC) Specific: The last 24 bits (6 hexadecimal digits) of the address. The manufacturer assigns this part, ensuring that every NIC they produce has a unique address.
Structure of a 48-bit MAC Address
ComponentBitsExample (00:1A:2B:3C:4D:5E)Description
OUI 24 bits 00:1A:2B Identifies the manufacturer (e.g., Dell, Cisco, Apple).
NIC Specific 24 bits 3C:4D:5E Uniquely identifies the specific device from that manufacturer.

From EUI-48 to EUI-64 and IPv6

The transition to IPv6 introduced a process to generate a unique 64-bit Interface ID for a device from its 48-bit MAC address. This is called the EUI-64 process and is a key part of IPv6 Stateless Address Autoconfiguration (SLAAC).

  1. Insert 'FFFE': The 48-bit MAC address is split in half, and the 16-bit hexadecimal value FFFE is inserted in the middle.
  2. Flip the 7th Bit: The 7th bit of the very first byte is flipped (from a 0 to a 1). This is known as the Universal/Local (U/L) bit and signifies that the address has been modified to form the Interface ID.

This resulting 64-bit Interface ID is then appended to a network prefix (like the Link-Local prefix FE80::/64) to form a complete, unique IPv6 address.

Professional Recommendation

While MAC addresses are "burned-in" to hardware, they can be changed or "spoofed" in software. For network security, relying solely on MAC filtering is not considered robust because an attacker can easily spoof a permitted address. Stronger security methods like WPA2/WPA3-Enterprise with 802.1X authentication should be used in business environments.

Frequently Asked Questions about MAC Addresses

What is a MAC address?

A MAC (Media Access Control) address is a unique 48-bit hardware identifier assigned to a network interface controller (NIC) for use as a network address in communications within a local network segment. It is a Layer 2 (Data Link) address.

How do I use this MAC address converter?

Enter a MAC address in any common format (e.g., 00:1A:2B:3C:4D:5E), select its type (usually EUI-48), and click 'Convert MAC'. The tool will provide various formats, the manufacturer's OUI, and the IPv6 Link-Local address.

What is an OUI?

OUI stands for Organizationally Unique Identifier. It is the first 24 bits (or first three octets) of a MAC address, which are assigned to a specific hardware manufacturer by the IEEE. An OUI lookup can tell you which company made the network device.

How can I find the vendor of a MAC address?

Our tool automatically performs an OUI lookup to find the vendor. By entering a MAC address, the 'OUI (Vendor)' field in the results will show you the name of the manufacturer associated with the first half of the address.

What is the difference between EUI-48 and MAC-48?

Functionally, there is no difference; the terms are often used interchangeably. EUI-48 (Extended Unique Identifier 48-bit) is the modern term for the same 48-bit address format that was previously known as MAC-48.

What is EUI-64?

EUI-64 is a 64-bit hardware identifier. It is often created from a 48-bit MAC address by inserting the hex value 'FFFE' in the middle of the address. This format is primarily used in IPv6 for generating Interface IDs.

How is a MAC address converted to an IPv6 Link-Local address?

An IPv6 Link-Local address (starting with FE80::) is often generated from a MAC address using the EUI-64 process. The 48-bit MAC is converted to a 64-bit EUI-64 address, and then the seventh bit of the first byte is flipped. This result becomes the Interface ID, which is appended to the FE80::/64 prefix.

How can I find my computer's MAC address?

On Windows, open Command Prompt and type `ipconfig /all`. Look for 'Physical Address'. On macOS or Linux, open the Terminal and type `ifconfig` or `ip addr show` and look for 'ether' or 'HWaddr'.

Is a MAC address the same as an IP address?

No. A MAC address is a permanent, hardware-level address used for communication on a local network (Layer 2). An IP address is a logical, network-level address used for routing across different networks (Layer 3). You need both for network communication.

What is the format of a MAC address?

A MAC address is a 48-bit number, typically represented as six groups of two hexadecimal digits. The groups can be separated by colons (00:1A:2B:3C:4D:5E), hyphens (00-1A-2B-3C-4D-5E), or dots (001A.2B3C.4D5E).

What is a unicast MAC address?

A unicast MAC address identifies a single, specific network interface. All standard MAC addresses assigned by manufacturers are unicast addresses.

What is a broadcast MAC address?

The broadcast MAC address is FF:FF:FF:FF:FF:FF. A frame sent to this address is delivered to all devices on the local network segment. It's used by protocols like ARP.

What is a multicast MAC address?

A multicast MAC address is a special address that represents a group of devices. They always start with `01-00-5E` for IPv4 multicast. Frames sent to a multicast MAC are received by all devices that have joined that multicast group.

What does UAA vs. LAA mean?

UAA (Universally Administered Address) is a MAC address assigned by the hardware manufacturer and is guaranteed to be globally unique. LAA (Locally Administered Address) is an address that has been manually changed by a network administrator, overriding the burned-in UAA. An LAA is identified by the 7th bit of the first byte being set to 1.

Can I change my MAC address?

Yes, most modern operating systems and network drivers allow you to 'spoof' or change your MAC address to a different one. This is often done for privacy reasons or to bypass MAC filtering on a network.

How can I generate a random MAC address?

You can use our MAC Address Generator to create valid, random MAC addresses, either with a random vendor OUI or as a Locally Administered Address (LAA).

Does my phone have a MAC address?

Yes, your phone has a unique MAC address for its Wi-Fi interface and another for its Bluetooth interface. However, for privacy, modern mobile operating systems (like iOS and Android) often use a randomized MAC address when connecting to Wi-Fi networks.

What is MAC filtering?

MAC filtering is a security feature on some routers and access points that allows you to create a list of approved MAC addresses that are permitted to connect to your network. However, it is considered weak security because MAC addresses can be easily spoofed.

What is a virtual MAC address?

Virtual machines (VMs) and virtualization platforms assign virtual MAC addresses to the virtual network interfaces of VMs. These addresses are often generated from a specific OUI assigned to the virtualization vendor (e.g., VMware or VirtualBox).

What is the colon-separated format used for?

The colon-separated format (e.g., 00:1A:...) is the standard notation used by Linux, macOS, and many other Unix-like systems.

What is the hyphen-separated format used for?

The hyphen-separated format (e.g., 00-1A-...) is the standard notation used by Microsoft Windows and its command-line tools like `ipconfig`.

What is the dot-separated format used for?

The dot-separated format (e.g., 001a.2b3c.4d5e) is the standard notation used by Cisco in their IOS and other networking equipment.

What layer of the OSI model do MAC addresses operate at?

MAC addresses operate at Layer 2, the Data Link Layer, of the OSI model. They are used for addressing frames within a single broadcast domain or local network.

Can two devices have the same MAC address?

A universally administered MAC address is globally unique. However, it is possible for two devices to have the same MAC address if one or both are using a locally administered (spoofed) address. If two devices with the same MAC address are on the same local network, it will cause a MAC address conflict and severe connectivity problems.

Does a network professional need to manage MAC addresses?

In most networks, MAC addresses do not require active management as they are hardcoded into devices. However, a network professional is needed for tasks that involve MACs, such as configuring MAC filtering, troubleshooting Layer 2 connectivity issues, or setting up virtualization platforms where MAC address pools may need to be managed.