Introduction to Networking - Interfaces and Protocols

As a follow-up to the networking terminologies article, it's time to let you know another some common and basic networking concepts. We will talk about common protocols and interfaces of networking.

Same like before, this article also operating system agnostic, but it should be very helpful when setting up features and services that use networking on your server.

Interfaces

Interfaces are ways for your computer to connect to other computers and networks. Each interface is linked to a physical or virtual networking device.

Normally, your server will have one configurable network interface per Ethernet or wireless internet card you have.

Also, a virtual network interface called the "loopback" or "localhost" interface will be set up. This is used to connect applications and processes on a single computer to applications and processes on other computers.

Administrators often set up one interface for traffic to the internet and another interface for a local area network (LAN) or private network.

Protocols

Putting different protocols on top of each other is how networking works. In this way, multiple protocols can be used to send one piece of data by putting them inside each other.

We'll talk about some of the most common protocols you might run into and try to explain how they differ and what part of the process they're used for.

We'll start with protocols that are used on the lower networking layers and work our way up to more abstract protocols.

Media Access Control (MAC)

Media access control is a way to tell devices apart through a communication protocol. During the manufacturing process, each device should get a unique media access control address (MAC address) that makes it different from every other device on the internet.

When you address hardware by its MAC address, you can refer to it by a unique value even if the software running on top of it changes the name for that device while it is running.

Media access control is one of the few link-layer protocols that you are likely to use frequently.

IP

The Internet Protocol is one of the basic protocols that make the internet work. Each network has its own IP address, which lets machines talk to each other across the network. In the TCP/IP model, it is set up on the Internet layer.

Networks can be linked together, but when traffic crosses between networks, it needs to be routed. This protocol assumes that the network is not reliable and that there are multiple ways to get to the same place, which it can switch between on the fly.

The protocol can be used in a number of different ways. IPv4 is the most common implementation today, but IPv6 is becoming more popular as an alternative because IPv4 addresses are getting harder to find and the protocols are getting better.

ICMP

ICMP is an acronym for "Internet Control Message Protocol". It is used to send messages between devices to let each other know when they are available or when there is an error. Tools like ping and traceroute use these packets to figure out what's wrong with a network.

Usually ICMP packets are transmitted when a packet of a different kind meets some kind of a problem. Basically, they are used to give feedback to network communications.

TCP

TCP stands for transmission control protocol. It is implemented in the transport layer of the TCP/IP model and is used to make connections that are reliable.

One of the protocols that wraps data into packets is TCP. Then, it sends these to the other end of the connection using the methods available in the lower layers. On the other end, it can check for errors, ask for certain pieces to be sent again, and reassemble the information into one logical piece to send to the application layer.

A three-way handshake is used by the protocol to build a connection before data is sent. This is a way for both parties to acknowledge the request and agree on a way to make sure the data is correct.

After the data has been sent, the same four-way handshake is used to break the connection.

TCP is the protocol of choice for many of the most popular uses for the internet, including WWW, FTP, SSH, and email. Without TCP, the internet we know today would not exist. 😎

Note: I also wrote an article about common and basic networking terminologies

UDP

UDP is an acronym for “User Datagram Protocol”. It is a popular companion protocol to TCP, and it is also used in the transport layer.

The main difference between UDP and TCP is that UDP doesn't send data in a reliable way. It doesn't check to see if the other end of the connection got the data. This seems like a bad thing, and in many ways, it is. But it is also very important for some functions.

UDP is much faster than TCP because you don't have to wait for confirmation that the data was received or be forced to send it again. It doesn't connect to the remote host; it just sends the data to that host and doesn't care if it is accepted or not.

It is useful for simple communications, like asking for network resources, because it is a simple transaction. It also doesn't keep a state, which makes it great for sending data from one machine to many real-time clients. Because of this, it's perfect for VOIP, games, and other applications that cannot afford delays.

HTTP

HTTP stands for Hypertext Transfer Protocol. It is a set of rules for how to talk on the web. These rules are written in the application layer.

HTTP defines a number of functions that tell the remote system what you are requesting. For example, GET, POST, and DELETE all interact differently with the requested data.

HTTPS

Hypertext Transfer Protocol Secure (HTTPS) is an extension of the Hypertext Transfer Protocol (HTTP). It is used for secure communication over a computer network, and is widely used on the Internet.

The principal motivations for HTTPS are to verify the website being accessed and to protect the privacy and integrity of the data being sent while it is in transit.

SMTP

The Simple Mail Transfer Protocol (SMTP) is an internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages.

FTP

FTP stands for File Transfer Protocol. It is also in the application layer and provides a way of transferring complete files from one host to another.

It is insecure by design, so it shouldn't be used on any network that is open to the outside world unless it is set up as a public, download-only resource.

DNS

DNS stands for Domain Name System. It is an application layer protocol used to provide a human-friendly naming mechanism for internet resources. It is what connects a domain name to an IP address and allows you to access sites by name in your browser.

SSH

SSH stands for Secure Shell. It is a protocol that uses encryption at the application layer and can be used to securely communicate to a remote server. Because this protocol can encrypt everything from end to end and is used so often, many other technologies are built on top of it.

There are many other important protocols that we haven't talked about yet. But this should give you a good idea of some of the fundamental technologies that make the internet and networking possible.

Conclusion

At this point, you should know some basic networking terms and be able to understand how different parts can talk to each other. This should help you understand other articles and the documentation of your system. 🎉🎉🎉

Thank you for reading 🙏. Feel free to share and/or react!