Ever wondered what magic happens behind the scenes when you type a website address into your browser and hit enter? It might seem like sorcery, but it’s actually a series of systematic steps your computer performs to bring that webpage to your screen. Let’s demystify this process using a simple example: visiting www.ourtelekom.com.sb. We’ll break it down into easy-to-understand chunks, perfect for beginners.
Before reading further, here is a list of terms and their definitions. These terms are used in this posts so I hope having a fair understanding of them first is vital to get the most out of this article.
| ARP (Address Resolution Protocol) | ARP stands for Address Resolution Protocol. It’s a protocol used by your computer to find the physical address (MAC address) of a device (like your router) on your local network using its IP address. Think of ARP as asking, “Who holds the address book in this local network?” |
| MAC Address (Media Access Control Address) | A MAC address is a unique identifier assigned to network interfaces for communications at the data link layer of a network segment. It’s like the unique code on each mailbox in an apartment complex, ensuring the mail (data packets) reaches the right doorstep. |
| IP Address (Internet Protocol Address) | An IP address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It’s akin to your home’s street address, allowing data to find its way to your device on the vast internet. |
| DNS (Domain Name System) | The Domain Name System is the phonebook of the internet, translating human-friendly domain names (like www.ourtelekom.com.sb) into machine-understandable IP addresses. DNS ensures you don’t have to remember a series of numbers to visit your favorite websites. |
| UDP (User Datagram Protocol) | UDP stands for User Datagram Protocol, a communication protocol used across the internet for especially time-sensitive transmissions such as video playback or DNS lookups. It’s like sending a text message where speed is crucial, and it’s okay if a message occasionally doesn’t get through perfectly. |
| TCP (Transmission Control Protocol) | Transmission Control Protocol is a standard that defines how to establish and maintain a network conversation through which application programs can exchange data. TCP is like making a phone call where you ensure the person on the other end hears every word correctly. |
| HTTP (Hypertext Transfer Protocol) | HTTP is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access. HTTP is akin to asking for a specific book in a library and being guided directly to its shelf. |
| HTTPS (HTTP Secure) | HTTPS is the secure version of HTTP, where communications are encrypted for security. This protocol is used when confidentiality is crucial, such as in banking or online shopping. It’s like sending a letter in a sealed, tamper-evident envelope instead of a postcard. |
| 3-Way Handshake | The 3-way handshake is a method used in a TCP/IP network to create a connection between a client and a server. It involves three steps: initiation, response, and acknowledgment. Think of it as the protocol for starting a conversation that ensures both parties are ready and willing to communicate. |
Imagine you’re sending a letter but only know the recipient’s name, not their address. That’s where your journey begins – finding the right address and ensuring your letter reaches its destination safely and correctly. Here’s how your computer accomplishes this:
Step 1: The search for the gateway
First, your computer needs to find the local network’s gateway, akin to finding out the post office’s location to send your letter. This is done through something called an ARP request, which is essentially asking, “Hey, where do I send this to get it to the wider world?” It’s a way of matching the internet’s version of a name (an IP address) with a physical location on your network (the MAC address of your router).
In simple terms, when you do a arp-a on your machine terminal or command prompt, you will see the mapping of IPs to MAC addresses. The are time s when an arp request did not find any entries in its arp table, in this case, to reach out beyond the LAN say to the internet the source mac address will be the address of the default gateway – router.
Step 2: Translating human-readable names (domain) into numbers (IP)
Next, your computer needs to know the exact address of www.ourtelekom.com.sb, which is done through a DNS request. Think of DNS as the internet’s phone book, converting website names (which are easy for humans to remember) into IP addresses (which computers use to identify each other). It’s like looking up the store’s address by its name before you can visit. DNS uses UPD on port 53 to communicate. UDP is not reliable compared to TCP.
Step 3: The 3 way handshake
Before any meaningful conversation happens, your computer and the website’s server need to agree on a secure way to communicate. This is achieved through the TCP 3-way handshake, a digital nod that ensures both parties are ready and willing to exchange information. It’s like knocking on someone’s door (SYN), they say “come in” (SYN-ACK), and you reply “I’m coming in” (ACK) before entering. As you can see there are three steps involved in the exchange, SYN, SYN-ACK, ACK where SYN refers to Synchronisation and ACK means Acknowledgement. TCP is connection-oriented which makes it a reliable form of communication protocol at the transport layer.
Step 4: Asking for Directions
With introductions out of the way, your browser now sends an HTTP request (or HTTPS for secure connections) using TCP to actually ask for the webpage’s content. This step is akin to asking your friend for the photo album you came to see. If the connection is secure (HTTPS), it’s like agreeing to speak in a secret language so no one else can eavesdrop.
Wrapping It Up
And there you have it! These four steps – ARP request, DNS lookup, TCP handshake, and HTTP/S request – are the backbone of how you access any website. It’s a fascinating dance of protocols and requests that happen in seconds, bringing the world to your fingertips. Next time you’re browsing the web, remember the incredible journey that each click represents.
Understanding these basics not only demystifies how the internet works but also deepens your appreciation for the complexities of modern technology. So, the next time you visit a website, remember the digital handshake and the seamless efforts that connect you to the vast expanse of the internet. Happy browsing!
This simple article seeks to explain how ARP, DNS, TCP, UDP work together at the transport layer. It is assumed that you know the definition of the acronyms.