Common Network Protocols You Should Know

Internet Protocol (IP)

The Internet Protocol (IP) is a set of rules that helps small segments of data, called packets, travel through the internet to the right destination. IP information is attached to each packet, which allows routers to send the packets to the correct place. Every device connected to the internet has a unique IP address, which helps the internet know where to send data. Once the packets arrive at their destination, the computer or device that receives them reassembles them. The next step depends on the transport protocol used in combination with IP.

Transmission Control Protocol (TCP)

TCP is a connection-based protocol means that it creates a connection between two devices before sending data. It uses a three-way handshake process to establish this connection which involves the exchange of “synchronize” and “acknowledge” messages between the client and server, followed by the exchange of data. TCP breaks data into smaller parts and sends them to the destination device, where they're put back together. If any parts are lost or damaged, TCP resends them to make sure the data is received correctly. This makes TCP a reliable way to send data over networks that aren't always reliable.

Usage: TCP is used by various networked applications, such as email clients, chat applications, and file transfer applications. It helps these applications establish a connection with a server and makes sure that messages are delivered without any errors.

Secure Shell (SSH)

SSH, also known as Secure Shell, is a method for secure remote login. It uses strong encryption to keep communications secure and maintain their integrity. It is based on Transmission Control Protocol (TCP) and employs a client-server model, which means that the connection is formed by the SSH client connecting to the SSH server. The client verifies the identity of the server using public key cryptography. Following the setup, the SSH protocol uses strong encryption and hashing to protect the data exchanged between the client and server.

Usage: When you need to securely access a remote computer or server, you use SSH to establish an encrypted connection and remotely control the system. Some of the commonly used SSH Clients are OpenSSH, PuTTY.

Simple Mail Transfer Protocol (SMTP)

Simple Mail Transfer Protocol, also referred to as SMTP, is a protocol used for sending and receiving emails over the internet. When you send an email, your email client utilizes SMTP to send the email to an SMTP server, which subsequently delivers it to the recipient's mail server. The SMTP client gives commands to the server to send data, like the sender’s email address, the recipient’s email address, and the email’s content. If both email addresses come from the same email domain, like gmail.com, the Mail Transfer Agent (MTA) or Message Transfer Agent (MTA) verifies that: If so, it immediately sends the email. If not, the server determines the recipient's domain using the Domain Name System (DNS) and then sends the message to the appropriate server.

Usage: When you send an email, your email client uses SMTP to communicate with the email server and transfer the message. Some of the commonly used email clients, are Microsoft Outlook, Apple Mail, and Gmail.

File Transfer Protocol (FTP)

File Transfer Protocol, or FTP for short, is a network protocol used for online file transfers between computers. The client-server architecture is based on TCP as well, and it connects users to FTP servers with FTP client software. After establishing a connection, the user can explore the server's files and folders, upload and download files, and carry out other file management operations.

Usage: When you need to transfer files between computers you use FTP to establish a connection and transfer the files securely. FileZilla is one of the most widely used file transfer software.

Hyper Text Transfer Protocol (HTTP)

HTTP, also called Hypertext Transfer Protocol, is a method of transferring data over the internet. It is used by web browsers and servers to share resources like images, HTML pages, and other types of data. It relies on TCP and follows a client-server model. A web browser requests a resource, like a web page or image, from a web server, which responds with the requested resource and a status code indicating if the request was successful. It is constantly evolving, and newer versions like HTTP/2 and HTTP/3 are intended to improve performance, security, and reliability.

Usage: When you browse a website, your web browser uses HTTP to request and receive web pages and other resources from the web server.

Transport Layer Security (TLS)

TLS, also known as Transport Layer Security, cryptographic protocol that make sure that information transferred over the internet is safe. It does this in three ways: by hiding the information from anyone who shouldn't see it, by making sure that the people exchanging the information are who they say they are, and by making sure that the information hasn't been changed by anyone along the way.

Usage: When you access a website that uses HTTPS, your web browser uses TLS to establish an encrypted connection and ensure that the data transmitted between your computer and the web server is secure.

Hypertext Transfer Protocol (HTTS)

HTTPS (Hypertext Transfer Protocol Secure) is a secure version of HTTP, means HTTPS uses encryption to increase the security of data transfer, which is especially important when users transmit sensitive data like logging into a bank account or email service. HTTPS uses Transport Layer Security (TLS) protocol to encrypt communications, which uses two different keys to encrypt communications between two parties: a private key and a public key. The private key is controlled by the owner of the website and is used to decrypt information encrypted by the public key, which is available to everyone who wants to interact with the server in a secure way.

Usage: When you access a website that uses HTTPS, your web browser uses HTTPS to ensure that the data transmitted between your computer and the web server is secure.

User Datagram Protocol (UDP)

UDP (User Datagram Protocol) is a connectionless protocol, mean it does not need to establish a connection before sending data. How it works is it splits up the data sent by an application into small packets called datagrams, each with a destination port number and checksum. These datagrams are then sent over the network to the destination host, where they are put back together to form the original message. Unlike TCP, UDP does not guarantee that data transmission will be reliable, and packets can be lost, duplicated or delivered out of order. However, UDP is faster and uses fewer resources than TCP, making it ideal for applications that require fast and efficient communication, such as online games or video streaming.

Usage: This protocol is used under the hood by some of the most popular audio and video streaming services, including Skype, Zoom, and Twitch.

Voice Over Internet Protocol (VoIP)

Voice over Internet Protocol (VoIP) is a protocol that allows you to make voice calls over a broadband Internet connection instead of an analog (regular) phone line.

Usage: When you make a phone call over the internet, VoIP is used to send audio data packets between your computer and the other person's computer. Skype, Zoom, and WhatsApp are just a few examples of popular applications that employ this protocol.

QUIC

QUIC (Quick UDP Internet Connections) is a relatively new network protocol developed by Google that provides a secure, reliable, and low-latency connection between clients and servers over the internet. QUIC is also being used as the underlying protocol for HTTP/3, the latest version of the HTTP protocol used for transmitting web pages and other data over the internet. As an alternative to HTTPS, which makes use of TLS built on top of the TCP protocol, QUIC is constructed on top of UDP. TCP requires multiple round trips to establish a connection, causing latency for the user. QUIC reduces latency by initiating encryption and exchanging keys in the initial handshake, which takes only one round trip. Although UDP is unreliable, QUIC handles lost data to ensure a seamless user experience.

Usage: Google Chrome uses QUIC as a transport protocol to establish a faster and more reliable connection with web servers.