You may have noticed a feature called MAC filtering or something similar.
This isnt the case, though.
IP addresses are used for routing traffic between networks.
Still, devices use MAC addresses to route data within a web connection.
Contents
What Is a MAC Address?
A MAC address is part of the layer 2 addressing scheme on theOSI model.
Layer 2 is used for local communication over a single connection.
In contrast, layer 3, with its IP addresses, is used for inter-web connection communications.
MAC addresses have a simple structure made up of 12 hexadecimal characters.
For example, a MAC address may look like this 00:20:91:AB:CD: EF.
Note:Hexadecimal means that the following characters are allowed 0123456789ABCDEF.
These make up a base 16 system.
Conveniently, this means that one 8-bit byte of data can be represented by 2 hexadecimal characters.
A MAC address is divided into two parts, split down the middle.
The MAC addresss first half identifies the devices vendor, manufacturer, or other organization.
It is an OUI, or Organisationally Unique Number assigned, upon request, by IEEE.
The second half of the MAC address is unique and assigned when a equipment is made.
This means that duplicates are likely with high-volume manufacturing.
Thankfully, the MAC address is only used in local connections and is never used for inter-data pipe communications.
It is possible to have an issue, but its unlikely.
These broadcasts are never extended out of a web link.
For this reason, there is no risk of anyone on the internet knowing your MAC address.
The information would only theoretically be helpful for someone on the same local internet as you.
IP addresses are the addressing scheme used to communicate across networks.
For this reason, you shouldnt share your public IP address where possible.
It says, I want to connect to these networks.
Are any of you out there?
This sounds fine until you realize your gear does this with a packet that uses its MAC address.
Or even internationally, wherever they have the infrastructure.
This denies anyone the ability to track your movements by monitoring the movement of a single MAC address.
MAC randomization is even generally enabled by default.
Both desktop and mobile operating systems allow you to manually override the MAC address.
This is useful and good for privacy.
It does have one minor consequence, though.
It means that MAC filters on Wi-Fi routers are generally easy to bypass.
A Humorous Side Note
A lot of organizations have been assigned OIDs by IEEE.
Many companies will be the ones youd expect, the actual hardware manufacturers.
Many will be companies youve never heard of too.
There are some interesting ones, though.
One such interesting one is the NSA.
Yes, everyonesfavoritethree-letter American agency is the National Security Agency.
They have the OID 00-20-91.
This is because its slightly more accessible for people to read and spot patterns this way.
This has been used to prank unwary system admins in companies.
Technically, there is no legal restriction or issue with doing this yourself.
Conclusion
A MAC address is a 48-bit address used for layer 2 communications.
Being a layer 2 addressing scheme, it never gets transmitted beyond the local web link.
However, a MAC address must be unique on a web link.
The MAC address has two halves.
The first half identifies the gear manufacturer, while the second half is a internet special gear identifier.
MAC addresses are assigned to a web connection adaptor when they are manufactured.
However, most operating systems feature functionality to override the given MAC address with a custom one.
MAC addresses are displayed as 12 hexadecimal digits, typically separated in pairs by colons or hyphens.
