In the vast realm of the internet, one URL stands out as the most universally recognized and visited: "https://www.google.com." We've all done it – that moment when we type those characters into our browser's address bar and eagerly press "Enter." But have you ever stopped to wonder what unfolds in the digital realm immediately after that click? What intricate processes are set into motion to generate the familiar list of search results that Google displays with astonishing speed?
If you've ever been curious about this, you're in the right place. Instead of just scratching the surface, we're about to dive deep into the heart of the matter.
Now, before we embark on this enlightening journey through the inner workings of the internet, let's make sure we're on the same page. You probably know what a web browser is, but if you don't, that's perfectly fine. A web browser is just the application you use to explore the vast world of the internet – think Chrome, Firefox, Safari, Edge, and the like.
In this article, we will explore fundamental concepts such as URL, DNS, TCP/IP, Firewall, Load Balancer, Webservers, Application Servers, and Database
A brief explanation of what happens when you type a URL into a web browser
When you type a web address like "https://www.google.com" into your browser and press Enter, a lot of stuff happens very quickly before you see the webpage. It all happens so fast that you might not even notice. Before we dive into the nitty-gritty details, let me give you a quick summary of what takes place in that split second.
Domain Name System (DNS) Request: Your computer asks a DNS server to find the IP address linked to "https://www.google.com." Think of the DNS server as an internet address book. It quickly sends back the IP address.
TCP/IP Handshake: Your computer uses the IP address to connect to the server through what's called a "TCP" connection. This connection is made possible using "IP." It's like a virtual handshake, ensuring your computer and the server can talk.
Firewall Check: If you have a firewall on your computer, it checks to make sure your request is allowed. The server you're trying to reach might have a firewall too, and it also checks to allow the connection.
Secure Connection (HTTPS): Your browser sends a request to the server using an encryption method like "SSL" or "TLS." This encryption keeps the information you share between your computer and the server secure. It's why you see the "s" in "https."
Load Balancer: Big companies like Google use multiple servers to handle lots of requests. They have a "load balancer" that directs requests to the right server. The load balancer is the traffic cop that ensures everything runs smoothly.
Request and Response: Your browser's request first goes to the load balancer, which forwards it to a specific server based on a specific algorithm. The server processes your request and sends a response back to the load balancer, which then passes it back to your browser.
Webpage Components: The response typically includes HTML, CSS, and JavaScript files that create Google's homepage. HTML tells your browser how to show the content, CSS styles it and JavaScript adds interactive features.
Dynamic Content: If there's dynamic content, like Google search results, the web server may ask the application server for data. The application server, in turn, could talk to a database server to get the needed data. This information is added to the response sent back to your browser.
Rendering: Your browser takes all the components it receives and puts together the webpage you see on your screen. It's like assembling a puzzle, and voilà, the page is ready for you.
So, the next time you enter a web address, remember that all these steps happen in the blink of an eye to give you the website you want to visit.
Can you imagine all the steps happening before a webpage appears on your browser? The overview I just gave is just a quick summary of the process. Now, let's take our time to explore each part in detail and see what goes on behind the scenes.
DNS Request Simplified:
Before your browser can even think about loading a website, it needs to know the web server's address. Here's how it figures it out:
Checking the Browser's Memory: When you type a web address like "google.com," your browser first looks in its memory to see if it remembers the address from before.
Cached Copy: If your browser finds the address, it uses it, which is faster. This memory is called a DNS record.
No Memory, No Problem: If your browser doesn't remember or if the address has changed, it asks the DNS server for help.
The Detailed DNS Lookup Process:
Here's what happens when your browser asks for help from the DNS server:
Local DNS Resolver: Your browser talks to the local DNS resolver, usually provided by your internet service provider (ISP). It's like asking a local guide for directions.
Checking the Local Memory: The local DNS resolver also checks if it remembers the address. If it does, it tells your browser right away.
Going Up the Chain: If the local DNS resolver doesn't remember, it sends a request to the top-level directory, called the root nameserver. Think of it as asking for directions from the very top.
Top-Level Directory: The root nameserver points to the top-level domain (TLD) nameserver, like ".com" or ".org."
TLD Directory: The TLD nameserver then guides your request to the authoritative nameserver for the specific domain.
Authoritative Guide: The authoritative nameserver knows the address you need and provides it.
Success!: The local DNS resolver now has the address and shares it with your browser.
Browser's Turn: Your browser finally knows where the website is and sends a request to the server at that address to get the webpage.
In some cases, there can be extra steps if the DNS record isn't found or if the website uses things like DNS load balancing or content delivery networks (CDN).
Once your browser knows the address, it keeps it for a while (the "TTL" or Time To Live) so that it can find the website faster the next time. The length of time it remembers is set by the website's owner.
TCP/IP Connection Simplified:
TCP (Transmission Control Protocol) and IP (Internet Protocol) are like the internet's handshake. They work together to connect your computer to a web server.
Here's how it works:
Asking for a Connection: When you enter "google.com" in your browser, it uses TCP/IP to ask the server for a connection.
Shake Hands: The server agrees to connect and sends a message back. This is like a digital handshake.
Requesting the Webpage: Once the handshake is done, your browser asks for the webpage you want (like Google's homepage). It uses TCP to make sure the request is sent and received correctly.
Getting the Webpage: The server sends back the webpage's code, using TCP again to make sure it arrives safely.
Putting It All Together: Your browser takes the code and shows you the webpage on your screen. It uses TCP/IP to fetch any other stuff the webpage needs, like images.
TCP/IP makes sure everything gets to your browser in the right order and without errors, so you see a complete and working webpage.
Firewall Simplified :
A firewall is like a digital security guard for your network. It watches the traffic coming in and going out and follows specific security rules to protect your network from things like hackers and harmful software.
When you type a web address like "google.com" in your browser, the request goes through the firewall on its way to the website's server. The firewall checks the request to see if it's okay based on its security rules.
There are two main types of rules the firewall uses:
Where is it from and where is it going?: The firewall checks if the request is coming from a safe place and going to the right place. For example, it might block requests from certain countries or only let in requests from certain known places.
What type of request is it?: The firewall also checks what kind of traffic the request is. It might block certain types, like those used by bad software, or only allow known and safe types, like web browsing.
If the request meets the firewall's security rules, it's allowed, and your browser can access the website. But if it doesn't meet the rules, it's blocked, and your browser can't get to the site. Firewalls help keep your network safe from unwanted or harmful stuff.
HTTPS/SSL :
HTTPS (Hypertext Transfer Protocol Secure) is a secure version of the HTTP protocol used to transmit data on the internet. It is used to encrypt the data transmitted between your browser and Google's server.
SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are encryption protocols that are used to secure the data transmitted over HTTPS.
When your browser establishes a connection with Google's server using HTTPS, your browser and Google's server first agree on the version of SSL/TLS to use and then create a secure, encrypted channel for transmitting the data.
Let me use an analogy to explain what is going on here.
HTTPS is like a locked box that is used to send messages over the internet. When you want to send a message using HTTPS, you put the message in the locked box and send it to the person you want to receive the message. Only the person you are sending the message to has the key to unlock the box and read the message.
SSL/TLS are like special codes that are used to lock and unlock the box. When you want to send a message using HTTPS, you and the person you are sending the message to agree on the code to use to lock and unlock the box. This way, only you and the person you are sending the message to know the code and can read the message.
When you type "google.com" into your browser, the browser is like the person sending the message. The server that hosts google.com is like the person receiving the message. The browser sends a request for the webpage using HTTPS, which is like putting the request in the locked box and sending it to the server. The server then sends the webpage back to the browser using HTTPS, which is like putting the webpage in the locked box and sending it back to the browser.
Load-Balancer :
Think of a load balancer as a traffic cop for the internet. Its job is to make sure that when you visit a website, the work is shared evenly among all the servers, sort of like distributing the load.
Imagine a giant website like Google, with billions of visitors every day. To handle all this traffic, Google uses many servers. A load balancer helps make sure no one server gets too overloaded, and the website keeps running smoothly.
So, when you want to go to "google.com," the load balancer takes your request and decides which server should handle it. This choice depends on a special rule called a load-balancing algorithm. This way, every server shares the work, and the website works well for everyone.
Web Server :
A web server is like the host at a restaurant. It's in charge of taking your order (request for a web page) and making sure you get the right meal (web page) in return.
So, when you want to visit "google.com," the server at Google gets the request from the load balancer. It then prepares the web page you asked for, including the HTML, CSS, and JavaScript that make it work.
Once it's done, the web server sends this prepared web page back to the load balancer. The load balancer forwards it to your browser, and your browser uses all those ingredients (HTML, CSS, and JavaScript) to show you the web page you wanted.
Application Server and Database :
While the web server handles the basic web page, the application server deals with the dynamic stuff. For example, when you search on Google, the application server takes care of finding the right results for your query.
Here's how it works:
Sending a Search: When you search on Google, your request goes to the load balancer, which forwards it to one of Google's web servers. This web server then sends the request to the application server.
Processing the Request: The application server takes your search query and figures out what results to show. If it's a complex query, like searching for a product on an online store, it might need help from a database to find the right information.
Database Help: For instance, if you're looking for a specific product, the application server might ask the database for details about that product.
Getting the Data: Once the application server has the data it needs, it sends it back to the web server. The web server then includes this data in the response it sends to your browser.
Showing You the Results: Your browser uses this information to display the search results on your screen.
So, while the web server handles the basics, the application server and the database, when needed, work together to give you dynamic content, like search results that change based on your query.
Rendering the Page :
When your browser gets the response from the web server, it's like receiving a package with all the pieces of a puzzle. Inside are the HTML, CSS, and JavaScript files that make up the webpage.
Here's what happens:
Arranging Content: Your browser places text and images where they belong on the page.
Styling Everything: It ensures everything looks nice by following CSS styles.
Making It Interactive: If there's JavaScript, your browser runs it, enabling buttons and dynamic effects.
Once your browser has done all this, you see the fully rendered webpage on your screen. Now you can click links, type in forms, and interact with the webpage as you please. It's like putting together a puzzle, and the webpage becomes alive for you to use.
Conclusion
In the world of web browsing, a simple click of the "Enter" key initiates a fascinating journey through the digital realm. From DNS requests to the rendering of web pages, numerous components work together seamlessly. DNS servers find addresses, load balancers distribute work, firewalls secure the path, HTTPS/SSL encrypts data, web and application servers provide content, and your browser assembles the final page. This process makes the internet an accessible and dynamic resource for all.