The Top Types of Internet Protocols Explained

The internet as we know it today simply would not function without protocols. Protocols are sets of rules and procedures that allow different computers and networks to communicate with each other seamlessly. Just like languages have grammar and vocabulary, data networks rely on protocols to provide a common framework for organizing and transmitting data.

Let’s explore some of the most important and widely used types of protocols that form the backbone of internet communication. Understanding these fundamental protocols will give you a deeper appreciation for how networks operate and exchange information.

TCP/IP: The Core Internet Protocol Suite

The Department of Defence designed and developed TCP/IP (Transmission Control Protocol/Internet Protocol) in the 1960s and is based on standard protocols. It is by far the most widely used protocol on the internet and local networks. 

TCP/IP is actually a suite of protocols that work together to handle the transmission of data over networks and the internet. Here’s a quick overview of how the main protocols work:

IP (Internet Protocol): The IP protocol handles addressing and routing of data packets between devices on a network. Each device gets a unique IP address that identifies it on the network. IP datagrams contain source and destination IP addresses to guide transmission.

TCP (Transmission Control Protocol): TCP builds on IP by establishing a reliable connection between two endpoints and ensuring ordered, error-checked delivery of data packets through features like flow control, segmentation, and acknowledgments.

UDP (User Datagram Protocol)

UDP offers a faster but less reliable transport layer protocol compared to TCP. It does not establish connectivity or check for errors, making it suitable for time-sensitive applications like video streaming.

HTTP: Accessing Web Content

This is one of the more well-known types of internet protocols. When you type a web address (URL) into your browser, HTTP (Hypertext Transfer Protocol) is the protocol your computer uses to request the content from a web server. HTTP works using a client-server model:

The client (web browser) sends an HTTP request message to the server hosting the content. This includes the URL of the requested resource.

The server processes the request, locates the file or resource needed, and sends back an HTTP response containing the content, like HTML, images, etc.

The client receives the response and renders the content on your screen.

HTTPS applies encryption (SSL/TLS) to HTTP requests and responses for secure transmission of sensitive data like passwords and credit cards.

SMTP: Sending Emails

SMTP (Simple Mail Transfer Protocol) facilitates the sending of email messages between servers, allowing you to easily exchange emails with recipients worldwide. Here’s how it works:

• Your email client (Outlook, Gmail, etc.) connects to your local SMTP email server.
• The email client sends the outgoing email message to your SMTP server.
• Your SMTP server forwards the email to the recipient’s SMTP server.
• The recipient SMTP server delivers the message to their email inbox.

This simple yet powerful protocol handles all transportation of email on the internet. SMTP doesn’t encrypt or protect data on its own, so SMTP-over-TLS is often used to add encryption.

FTP: Transferring Files

FTP (File Transfer Protocol) allows users to transfer files between networked devices. It’s used for uploading web pages and other content to web servers. FTP uses two main channels:

Control channel: Clients send commands like GET, PUT, DELETE through the control channel to request files from the server.

Data channel: The actual file contents are sent over the data channel after the control dnschannel establishes connection.

FTP transmits data in clear text, so Secure FTP (SFTP) or FTPS are better options if encryption is needed. However, standard FTP is still widely used due to its simplicity.

DNS: Resolving Domain Names

DNS (Domain Name System) serves as the internet’s directory service by translating domain names that humans can easily remember (e.g., google.com) into numerical IP addresses that computers use to communicate (e.g., 142.250.184.206).

This translation is necessary because while we prefer to use descriptive website names, routers and servers identify sites based on their IP addresses. DNS servers contain databases that map domain names to their corresponding IPs.

When you type a domain name into your browser, it first contacts a DNS resolver to get the IP address for that domain before retrieving the website content using HTTP.

DHCP: Dynamically Assigning IP Addresses

As mentioned above, every device on a network needs an IP address. But manually configuring static IP addresses on every device is extremely tedious.

This is where DHCP (Dynamic Host Configuration Protocol) comes in handy! DHCP automates IP address management by dynamically assigning addresses to new devices as they join the network.

When a DHCP client device connects, the DHCP server leases it an available IP address from a preconfigured pool of addresses. This lease has an expiration time, after which the IP can be assigned to another device.

DHCP is a type of internet protocol that makes life much easier for home users and network admins!

SSH: Securing Remote Logins

SSH (Secure Shell) enables secure remote access to devices through encrypted connections. It is commonly used as a more secure replacement for protocols like Telnet and FTP that transmit data in plaintext.

SSH uses public-key cryptography to authenticate users and create encrypted tunnels between endpoints. All traffic flowing through these tunnels is encrypted. This prevents snooping or tampering with sensitive data.

System administrators rely on SSH daily to securely manage servers, network devices, and other infrastructure through remote terminal sessions.

POP3 and IMAP: Retrieving Emails

We’ve seen how SMTP delivers your emails – but how exactly does your email client software fetch new messages from the server? This is handled by POP3 and IMAP protocols.

POP3 (Post Office Protocol v3): This simpler protocol downloads all new emails from the server onto your local computer for offline access. Once downloaded, the messages are normally deleted from the server.

IMAP (Internet Message Access Protocol): IMAP keeps all messages stored on the server instead of downloading them. Users can manage email folders online and access their inbox from multiple devices.

IMAP is more flexible, but POP3 may be preferred for offline usage. Most modern email services and clients support both protocols.

IPv4 and IPv6: IP Addressing Schemes

IP addressing relies primarily on two standards: IPv4 and IPv6:

IPv4: The fourth version of IP uses 32-bit addresses split into four octets. This allows for approximately 4 billion unique addresses – a limit we’ve now reached.

IPv6: The newest 128-bit IPv6 addresses solve the address shortage by supporting a massive number of IP address combinations running into billions of trillions! IPv6 is slowly replacing IPv4 on networks and devices.

Understanding the differences between IPv4 vs IPv6 is key knowledge for network engineers as adoption of the newer standard increases.

Bringing the Internet to Life

While we’ve only covered some of the most common ones here, dozens of protocols work in unison to facilitate communication and data exchange across the global internet as well as private networks.

Each plays a specific role in powering different aspects of networking: establishing connectivity, transferring files, routing packets, resolving names, securing transmissions, and more.

Mastering foundational types of internet protocols helps build a strong understanding of how network communication actually takes place step-by-step. So take some time to read up on and experiment with these fundamental protocols powering connectivity!