The Network interface card(NIC) is a computer hardware component that connects a computer to a computer network. The NIC has physical layer and data link layer device as it provides physical access to a network through (Media Access Control) MAC address.
The NIC is also known as a network interface controller, network adaptor, LAN adaptor or physical network.
NIC is the electronic circuitry required to communicate using a specific physical layer and a data link layer standard such as Ethernet or Wi-Fi and also provides a base for a full network protocol stack allowing communication amongst the group of computers on the same local area network and large-scale network communications through routable protocols such as Internet Protocol.
How a network interface card aka NIC works
NICs are compact, and it has an antenna connection that the network interface card makes, so the signals come from this wire and then of course it connects to these pins which go into the computer, so the computer can understand the thing that you’re trying to communicate with.
When bits come in they are organised into what’s called frames and within the frame you have a destination address, so they know where the data will be sent, now the header of the frame is removed because it is no longer necessary and the rest of the data is sent to the network protocol.
If data comes in to your network interface card with TCP protocol your computer will know what to do with it so now that the data has come through to a specific network protocol we’re in that area where if you’ve closed or blocked the ports the data won’t move forward in other words if you haven’t given it the green light.
For example HTTP protocol that hat goes through this handshake where first the server that you’re communicating with has agreed to synchronize with you, so a port has opened up for HTTP we’re talking about port 80 this port has opened up, and the computer is expecting something to come in then the computer accepts it, so it goes through because you initiated the connection if you’ve blocked a port or you didn’t initiate data to come in through a particular port then the computer might reject it.
Modern network interface cards offer advanced features such as interrupt and DMA or Direct Memory Access interfaces to the host processors support for multiple receive and transmit queues partitioning into multiple logic interfaces.
What’s the difference between a packet and a frame
When you have requested off the Internet the frame gets chopped off by the network interface card and this gets sent over to or through my computer it’s just the opposite when we’re talking about the bits being transmitted out so if you’re sending a picture to somebody and you’re to identify your IP and then the destinations IP. You’ll put that in the network interface card it throws a MAC address on and sends it on its way.
Who creates the MAC address of your computer
As you probably know that you can always change your IP address and some IP address are changed automatically as long as you are following the rules of RFC 1918 which comes under private network, you’re allowed to change your IP address.
In MAC address no matter how big or small that network interface card is it’s the manufacturer who creates this MAC or physical address can have their own rules to play by as a business they know these rules.
But you could actually spoof a MAC and one of the biggest reasons you don’t want to start changing MAC addresses is because if there are two MAC addresses on the network it’s not going to work properly and that’s why these are stored on the network interface cards ROM this is read-only memory Mac’s not supposed to change but since nothing is impossible in computer science there are always ways you can spoof a MAC address.
Working of MAC address
There are two parts to every MAC number the first 24 bits are the manufacturers IDs this is called OUI which stands for organizationally unique identifier and the second is basically the serial number of them that the manufacturer created of that device of that thing that you have so Mac media access control address.
MAC address formats are as follows:-
So a MAC address is made up of a total of 48 bits and these are usually displayed to us in 12 hexa digits.
MAC address is larger than traditional IPv4 address.