Day 1 — ইন্টারনেট আসলে কীভাবে কাজ করে

The day began with a phone call to a boy named Akash. His serious tone informed him that there was an issue with his bank account and the account would be frozen if not resolved immediately. Akash received an OTP, which he quickly entered, and shortly after, he received a message stating that his entire account balance had been stolen. Reflecting on this incident, one might wonder how such a transaction could occur and what role the internet played in it.

At its core, the internet is simply a vast network of interconnected computers and devices. Imagine a neighborhood with houses connected by streets - the internet works in a similar manner. Each house represents a computer or machine, and the streets are the cables connecting them all. This connection allows computers across the globe to communicate with each other.

The internet originated from a secret military network called ARPANET, developed by the U.S. defense system to share classified data. It started as a tool for government use, but over time, it evolved into the expansive network we know today, known as the World Wide Web (WWW).

When you want to find something specific on the internet, like a website, you type in the URL, which is essentially the address of that site. Just like asking a friend or family member to take you to a specific store, your computer follows a series of steps to find the website you want. This is facilitated by the Domain Name System (DNS), which acts like a phonebook for the internet, translating human-readable domain names into computer-friendly IP addresses.

To establish a connection between two computers on the internet, certain rules and protocols must be followed. One such protocol is TCP/IP, which helps in the smooth transfer of data between computers. Think of it as a set of rules governing how messages are sent and received over the internet, ensuring that data is formatted correctly and delivered efficiently.

When it comes to data security, encryption plays a crucial role. Imagine sending a letter in a locked box, with the key only known to the sender and the recipient. If someone intercepts the letter, they won't be able to read its contents without the key. SSL (Secure Sockets Layer) serves a similar purpose, encrypting data before it's sent over the internet, ensuring that even if intercepted, the data remains unreadable to unauthorized parties.