While IP addresses are hierarchical and assigned by routers (See article: What is A Static IP?), MAC Addresses do not have an assignment rule. Each piece of hardware that can be connected to a local network has a unique MAC address (which has nothing to do with Apple computers), in addition to the IP address assigned by the router or internal server. MAC stands for Media Access Control and is composed of 6 octets separated by a dash (e.g. 00-50-FC-A0-67-2C ).
The question that arises is: What exactly is the physical MAC address or MAC Address, how is the MAC Address for Ethernet and wifi and what is its function?
MAC addresses, also called physical addresses, ethernet addresses or LAN addresses, are uniquely assigned to network cards, both ethernet and wireless . The packets that are sent on the ethernet must always come from a MAC address, destined for another MAC Address. When a network card receives a packet, it checks that the packet has actually been sent to its MAC address otherwise it discards it.
There are special MAC addresses, such as ff: ff: ff: ff: ff: ff, which is the broadcast address of each ethernet network adapter.
Physical MAC addresses are a low-level component of an Ethernet network (and some other similar standards, such as Wi-Fi networks). They allow a device to communicate with a machine on the local physical network (LAN) without using the Internet .
On the contrary, IP addresses cover the entire Internet and are managed by routers that use them to understand where to send data.
MAC addresses are required to have a specific function within a local Ethernet or Wifi network.
They allow a network card to draw attention to a single directly connected device, even if the physical connection was shared. This can be important when thousands of devices are connected together in one organization.
In practice, MAC addresses, at home level, are a negligible concept except in rare cases that we will see at the end of the article.
To really understand what role MAC addresses play in the transmission of packets in a network it is necessary to understand the OSI stack . The OSI stack is a theoretical graphic model made of 7 layers that represent the transmission steps of a packet between two applications running on separate machines that do not have a direct physical connection. The computer network has been divided into layers and each layer can speak to the corresponding layer on a remote computer. The layered OSI model works a bit like a nested postal system: the application creates its data, envelops and sends it, the operating system takes it, puts it in another envelope and sends it back to the network driver, network drivers sends it in another envelope to the physical cable and so on.
- The bottom layer, layer 1 is the physical layer made of wires, transistors and radio waves. The data here goes wherever it is physically connected, including the ethernet network cable. - Level 2 is the data link level that corrects errors and provides indications on which device is physically connected. This is the level at which MAC addresses come into play.
- Layer 3 is the network layer where IP addresses work, where computers transmit messages that can reach any machine anywhere on the "network" without needing to be in direct connection.
- Levels 4-7 are higher level protocols. TCP, for example, is located above the IP protocol and provides mechanisms for addressing missing packets.
MAC addresses therefore work at level 2 and allow 2 machines that are physically connected to each other, to exchange data and messages which will be ignored by other machines that share the same physical connection.
How do IP addresses and MAC addresses work together "> configuring a wifi router at home you could activate the MAC Address filter so as to allow only specific devices to access the network.
DHCP servers use the MAC address to identify devices and give them fixed IP addresses.
READ ALSO: How computers talk to each other on the network via TCP / IP
The question that arises is: What exactly is the physical MAC address or MAC Address, how is the MAC Address for Ethernet and wifi and what is its function?
MAC addresses, also called physical addresses, ethernet addresses or LAN addresses, are uniquely assigned to network cards, both ethernet and wireless . The packets that are sent on the ethernet must always come from a MAC address, destined for another MAC Address. When a network card receives a packet, it checks that the packet has actually been sent to its MAC address otherwise it discards it.
There are special MAC addresses, such as ff: ff: ff: ff: ff: ff, which is the broadcast address of each ethernet network adapter.
Physical MAC addresses are a low-level component of an Ethernet network (and some other similar standards, such as Wi-Fi networks). They allow a device to communicate with a machine on the local physical network (LAN) without using the Internet .
On the contrary, IP addresses cover the entire Internet and are managed by routers that use them to understand where to send data.
MAC addresses are required to have a specific function within a local Ethernet or Wifi network.
They allow a network card to draw attention to a single directly connected device, even if the physical connection was shared. This can be important when thousands of devices are connected together in one organization.
In practice, MAC addresses, at home level, are a negligible concept except in rare cases that we will see at the end of the article.
To really understand what role MAC addresses play in the transmission of packets in a network it is necessary to understand the OSI stack . The OSI stack is a theoretical graphic model made of 7 layers that represent the transmission steps of a packet between two applications running on separate machines that do not have a direct physical connection. The computer network has been divided into layers and each layer can speak to the corresponding layer on a remote computer. The layered OSI model works a bit like a nested postal system: the application creates its data, envelops and sends it, the operating system takes it, puts it in another envelope and sends it back to the network driver, network drivers sends it in another envelope to the physical cable and so on. - The bottom layer, layer 1 is the physical layer made of wires, transistors and radio waves. The data here goes wherever it is physically connected, including the ethernet network cable. - Level 2 is the data link level that corrects errors and provides indications on which device is physically connected. This is the level at which MAC addresses come into play.
- Layer 3 is the network layer where IP addresses work, where computers transmit messages that can reach any machine anywhere on the "network" without needing to be in direct connection.
- Levels 4-7 are higher level protocols. TCP, for example, is located above the IP protocol and provides mechanisms for addressing missing packets.
MAC addresses therefore work at level 2 and allow 2 machines that are physically connected to each other, to exchange data and messages which will be ignored by other machines that share the same physical connection.
How do IP addresses and MAC addresses work together "> configuring a wifi router at home you could activate the MAC Address filter so as to allow only specific devices to access the network.
DHCP servers use the MAC address to identify devices and give them fixed IP addresses.
READ ALSO: How computers talk to each other on the network via TCP / IP
