What Is a MAC Address?
Tips on how to find a MAC address, Identifying
Unknown Devices, DHCP, and more.
Last updated: October 09, 2009
When you think about networking, IP addresses are
probably the first things that come to mind. But there's another type of
network address called a
MAC address that actually forms the foundation
upon which IP address communication is built, at least where local area
networks are concerned.
What Is a MAC Address?
A
MAC (Media
Access Control) address, sometimes referred to as a hardware
address or physical address, is an ID code that's assigned to a
network
adapter or any device with built-in networking capability, such as a
printer. While an
IP address can potentially be assigned to any device,
a MAC address is "burned into" a given device from the factory. A
MAC
address takes the form of six pairs of
hexadecimal digits, usually
separated by colons or dashes and will look something like
this: 01:1F:33:69:BC:14. Hexadecimal digits can include only the
numbers 0-9 and letters A-F.
The first three pairs
of digits in the MAC address are called the
OUI (Organizational
Unique
Identifier), which identifies the company that manufactured or sold the
device. For example, a
MAC address that begins with 00:1F:33 denotes a Netgear product. The last three pairs of digits are specific to the
device and can be more or less considered a serial number of sorts.
Together, the two parts of the MAC address form an ID that's unique to a
particular device.
To understand how
MAC addresses are used,
first consider that when you type www.smallbusinesscomputing.com into
your Web browser, it can't get there until a
DNS (Domain
Name Service)
server looks up the corresponding IP address for the
Web site allowing a
connection to take place. While MAC addresses don't have any real
significance on the
Internet, they're used in a similar way on a
LAN (local area network).
Given that IP addresses can't be permanently
assigned to a device — after all, a particular address can belong to one
computer today and another one tomorrow — MAC addresses allow
communication between devices on a local network by making it possible
to reliably distinguish one computer from another. Just as
DNS matches a
Web site name to an IP address on the Internet, a technology called
ARP
(Address Resolution Protocol) matches an IP address to the corresponding
MAC address of a specific device to which that IP address is currently
assigned.
Article excerpt
courtesy of SmallBusinessComputing.com
Joe Moran spent six years
as an editor and analyst with Ziff-Davis Publishing and several more as
a freelance product reviewer. He's also worked in technology public
relations and as a corporate IT manager, and he's currently principal of
Neighborhood Techs, a technology service firm in Naples, Fla. He holds
several industry certifications, including Microsoft Certified Systems
Engineer (MCSE) and Cisco Certified Network Associate (CCNA).
A Networking Primer: What's a MAC Address?
Joe Moran shows you how to find a MAC address and offers three tips on
using them.
The OSI Reference Model — Understanding Layers
It is time to take a trip up the OSI Reference Model, and learn what
this mysterious thing is all about. The network stack is of great
significance, but not so much that it's the first thing you should
learn. Many so-called networking classes will start by teaching you to
memorize the name of every layer and every protocol contained within
this model. Don't do that.
Understanding And Resolving IP Address Conflicts
IP address conflicts are usually temporary, but you can't count on them
to always resolve themselves. This week, we'll look at likely causes of
IP address conflicts and some ways to address them.
Cloning your MAC address
Some ISPs have started to recognize the MAC addresses of popular routers
and disconnect service if a router is detected. Fortunately, many router
manufacturers are including the capability to either set the router WAN
port MAC address to anything you want.
What's
a MAC Address and How Do You Find It
To ensure optimal wireless network security, a little MAC (Media Access
Control) filtering couldn't hurt. Learn what a MAC address is and how to
find your's ... plus, why some online games
may be dropping you. |
