Principle 1: The Need to Share Information
The most fundamental truth is that we have information on one computer (Computer A) and we want it to be on another computer (Computer B). These computers are not in the same room.
How do we solve this? The simplest, most primitive way is to physically carry the information (e.g., on a USB stick). This works, but it's slow and doesn't scale. We need a direct, electronic connection.
So, we run a cable (like an ethernet cable or a fiber optic line) between Computer A and Computer B. We can now send electrical signals or pulses of light down this cable. We can agree on a simple code: a high-voltage signal means "1," and a low-voltage signal means "0".
We have just created the most basic form of a network: a direct link. We can now send bits (1s and 0s) between two computers.
Principle 2: The Problem of Scale
This works for two computers. But what if we have three computers (A, B, and C) and they all need to talk to each other? We would need a cable from A to B, from B to C, and from A to C. For four computers, we'd need six cables. For 100 computers, we'd need 4,950 cables.
This is a failure of scale. Connecting every machine to every other machine directly is physically impossible.
The logical solution is to have a central device. Every computer connects to this one central point (let's call it a Switch). When Computer A wants to talk to Computer C, it sends the message to the switch, and the switch forwards it only to Computer C.
We have just invented a Local Network. A group of computers in close proximity (like an office or a home) can now communicate efficiently.
Principle 3: The Problem of Connecting Networks
Now, our office has a local network. Another office across town also has its own local network. How does a computer on our network talk to a computer on their network?
We face the same scaling problem. We can't run a wire from every computer in our office to every computer in theirs.
The logical solution is to connect the networks themselves. We need a special, dedicated computer that is connected to our network and also connected to their network. Its only job is to pass messages, or "route" traffic, from one network to the other. Let's call this device a Router.
Now, if we want to connect to a third network, we just connect our router to their router. Suddenly, we can build a massive, sprawling web by connecting networks to other networks.
This is the fundamental truth of the Internet. The Internet is a "network of networks".It is not one giant cloud; it is millions of private and public local networks all connected by these special routing devices.
Principle 4: The Problem of Finding Anyone (Addressing)
We have built a global web of interconnected networks. If I'm on my computer in my office, how do I send a message to a specific server in another country? There are millions of computers. I need a unique address for every single device.
This gives rise to the need for a universal addressing system. Just like the postal service needs a unique street address for every house in the world, our network of networks needs a unique address for every connected device.
This isthe reason the IP Address (Internet Protocol Address)exists. It's a unique label (e.g.,142.250.184.142) assigned to each device. When a router sees a message, it looks at the destination IP address and says, "Based on this address, I don't need to send it to the network on my left; I need to send it to the network on my right to get it one step closer to its final destination." Routers don't know the full path; they just know the next best "hop" to send the message on.
Principle 5: The Problem of Reliability and Fairness
If I want to send a large file, like a 1-hour video, it is a huge stream of data. If I try to send it all at once:
This is inefficient and unreliable. The logical solution is to break the large file into many thousands of small, numbered pieces. Let's call them Packets.
Each packet is like a tiny envelope. It contains:
These packets can travel independently across the internet, sometimes even taking different routes. The receiving computer gathers all the packets, checks if any are missing (and requests them again if they are), and reassembles them in the correct order to recreate the original file. This system of rules for addressing, breaking down, sending, and reassembling data is called a Protocol. The main one used on the internet is TCP/IP (Transmission Control Protocol / Internet Protocol).
So, the internet isn't magic. It's a series of logical solutions to a series of fundamental problems:
An IPv4 (Internet Protocol version 4) address is the classic IP address format everyone is used to seeing.
When the internet was designed, 4.3 billion seemed like an infinite number. But with the explosion of laptops, phones, servers, smart watches, and even smart refrigerators, we quickly realized we would run out. This scarcity is the single most important reason we have public and private IPs.
A Public IP address is your global, unique address on the internet.
When you go to a site like whatismyip.com, it shows you the Public IP address of your router. From the internet's perspective, your entire home network looks like a single device with that one public address.
A Private IP address is a local address used only within your own private network (e.g., your home Wi-Fi, your office network).
IPv6 (Internet Protocol version 6) is the next generation of the Internet Protocol. Its primary purpose was to solve the address exhaustion problem of IPv4.
The fundamental difference is the size of the address:
The difference between 32-bit and 128-bit is not 4x. It's an exponential leap that is difficult to comprehend.
The number of possible IPv6 addresses is 2^128, which is roughly:
340,000,000,000,000,000,000,000,000,000,000,000,000 (340undecillion)
Because it's so long, the format is different. It uses hexadecimal (numbers 0-9 and letters a-f) instead of just decimal numbers.
An example of a full IPv6 address: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
It's broken down into:
A MAC (Media Access Control) Address is a unique, permanent serial number burned into every network-capable piece of hardware (your laptop's Wi-Fi card, your phone, your smart TV, the network port on your desktop).
To track you, if you get offline and someone get the ip, they will get your message.
A MAC address is a 48-bit number. To make it readable for humans, it's typically written as 12 hexadecimal digits.
The most common ways you'll see it displayed are:
If you only want to see the MAC addresses without all the other details, you can use the (getmac /v) command.
Port numbers are numerical identifiers (0-65535) in computer networking that identify specific applications or services on a device. They work with IP addresses to direct network traffic to the correct service on a machine, with common ports assigned to standard applications like HTTP (port 80) and HTTPS (port 443).
A port number is a 16-bit unsigned integer.
Let's break that down:
Because it's a 16-bit number, the total number of possible ports is 2^16, which equals 65,536.
To prevent chaos, the internet authorities (IANA) have divided the 65,536 available ports into three categories. This is the most practical format for you as a developer to understand.
These are the VIPs of the port world. They are reserved for the most common, fundamental, and standardized internet services.
These ports are for specific applications or services that are not as universal as the "well-known" ones. Companies and developers can register a port for their software to avoid conflicts with other applications.
These ports are not meant for public-facing servers. Their job is completely different.
DNS is the global, distributed system that translates the human-friendly domain names into the computer-friendly IP addresses. Without it, you'd have to memorize hundreds of IP addresses to browse the web.
Before your computer does any work, it checks if it already has the answer. Speed is everything. It checks in this order:
If the IP address is found in any of these caches, the process stops here, and your browser immediately connects to the IP address. This is why websites you visit often load so quickly.
If the answer isn't in any local cache, your computer needs to ask for help. It sends a query to its configured Recursive DNS Resolver.
The Recursive Resolver doesn't know every IP address in the world. Instead, it knows how to navigate the global DNS system, which is a giant, hierarchical tree. It starts from the top and works its way down.
Now, finally, your browser has the IP address it needs. It can now open a direct connection to 142.250.72.206 on port 443 (for HTTPS) and say, "Please send me the webpage for www.google.com."
The DNS process is complete.
