What happens when you type https://www.google.com in your browser and press Enter?

Introduction

Have you ever wondered what happens when you type a website's URL into your browser and press enter? Behind the scenes, a complex series of processes and interactions take place to ensure that you can access the website's content quickly and securely.

In this blog post, we'll explore the various components involved in the process of accessing a website, from the initial DNS request to the final delivery of content to your browser. We'll examine the roles of:

• DNS request
• TCP/IP
• Firewall
• HTTPS/SSL
• Load-balancer
• Web server
• Application server
• Database

and how all these works together to deliver website content.

By the end of this post, you'll have a deeper understanding of the technology behind website infrastructure and the critical roles each component plays in ensuring website availability, performance, and security. So, let's dive in and explore the inner workings of website access!

DNS Request:

The first step is the DNS (Domain Name System) request. When you type https://www.google.com into your browser, your computer sends a DNS request to a DNS server to obtain the IP address associated with the domain name. The domain name is essentially the human-friendly name that we use to access a website, while the IP address is a unique identifier assigned to each device connected to the internet.

The DNS server acts as a phonebook for the internet, translating domain names into IP addresses. When your computer sends a DNS request, it asks the DNS server to provide the IP address associated with the domain name you entered.

The DNS server first checks its cache to see if it has the IP address for the domain name. If it does, it returns the IP address to your computer, and your browser establishes a connection with the server. If the DNS server does not have the IP address in its cache, it forwards the request to other DNS servers until it finds the correct IP address.

This process of forwarding DNS requests from one DNS server to another continues until the IP address is found. This is because there are millions of websites on the internet, and no single DNS server can store all the IP addresses for all the domain names.

Once the DNS server returns the IP address to your computer, your browser uses it to establish a connection with the server hosting the website you want to access. This connection is established using TCP/IP (Transmission Control Protocol/Internet Protocol), which ensures reliable and error-free communication between your computer and the server.

TCP/IP:

Once the IP address is obtained, your browser establishes a TCP/IP (Transmission Control Protocol/Internet Protocol) connection with Google's server. TCP is a connection-oriented protocol that ensures reliable and error-free communication between two devices over a network. When your computer establishes a TCP connection with the server hosting the website, the two devices exchange packets of data to ensure that they are both ready to communicate.

The process of establishing a TCP connection involves three steps: the SYN (synchronize) packet, the SYN-ACK (synchronize-acknowledge) packet, and the ACK (acknowledge) packet. When your computer sends a SYN packet to the server, it requests that the server establish a TCP connection with it. The server responds with a SYN-ACK packet, indicating that it is willing to establish a connection. Finally, your computer sends an ACK packet to the server, confirming that the connection has been established.

Once the TCP connection is established, your computer can send and receive data from the server hosting the website. The data is divided into packets and sent over the network using IP, the Internet Protocol. IP is responsible for routing packets from the source device to the destination device over the internet.

When a packet arrives at its destination, it is reassembled into the original data and processed by the receiving device. If any packets are lost or corrupted during transmission, TCP ensures that they are retransmitted, ensuring that the data is received correctly.

Firewall:

Before the request reaches Google's server, it goes through a firewall. A firewall is a security device that sits between your computer and the internet, filtering network traffic to prevent unauthorized access to your computer or network. When you enter a website's URL into your browser, your computer sends a request to the website's server, and the server responds by sending data back to your computer. During this exchange of data, a firewall can analyze the data packets and filter out any malicious or unauthorized traffic.

A firewall can work in several ways. One common approach is to use packet filtering, where the firewall examines each packet of data as it passes through and blocks any packets that do not meet certain criteria. For example, a firewall may block packets that come from an untrusted source or that use a protocol that is known to be vulnerable to attacks.

HTTPS/SSL:

After passing through the firewall, your browser initiates an HTTPS (Hypertext Transfer Protocol Secure) connection with Google's server. HTTPS (Hypertext Transfer Protocol Secure) is a protocol that encrypts data between your computer and the server hosting the website you are accessing. This encryption is provided by SSL (Secure Sockets Layer) or its successor, TLS (Transport Layer Security), which are cryptographic protocols that provide secure communication over the internet.

When you access a website that uses HTTPS, your computer and the server first establish a TCP connection, as described earlier. The server then sends a digital certificate to your browser, which contains information about the website's identity and the public key needed to establish an SSL/TLS connection.

Your browser then uses the public key to encrypt the data that is sent to the server, ensuring that it cannot be intercepted and read by unauthorized parties. The server then uses its private key to decrypt the data and send a response back to your browser, which is also encrypted using SSL/TLS.

The use of HTTPS/SSL provides several benefits. First and foremost, it ensures the confidentiality and integrity of data transmitted between your computer and the website's server. This prevents attackers from intercepting and reading sensitive information, such as login credentials or credit card details.

In addition, HTTPS/SSL provides authentication, which ensures that you are communicating with the website you intended to access, rather than an imposter. This is especially important for websites that require sensitive information, such as banking or e-commerce websites.

Load-Balancer:

At the time you type google.com into your browser, stop for a second to think how many people are typing the same thing, or how many people are using a site at the same time? How can they all go there and still access it when there are so many servers? How come there is no low traffic to the site? That is where load balancing comes in.

Google's server is most likely equipped with a load-balancer, which distributes incoming traffic across multiple servers to ensure that no single server is overwhelmed. A load balancer is a device or software that distributes incoming network traffic across multiple servers. This helps to improve website performance, availability, and scalability by ensuring that no single server becomes overwhelmed with traffic.

When you enter a website's URL into your browser, your computer sends a request to the website's server. If the website uses a load balancer, the request is first sent to the load balancer, which then forwards the request to one of the servers in the server pool.

Load balancing can be done in several ways, including round-robin, where requests are distributed evenly across all servers, or based on server health, where the load balancer sends requests to the server with the lowest current load.

Load balancing helps to improve website performance by ensuring that incoming requests are handled quickly and efficiently. It also helps to ensure website availability by providing redundancy, so that if one server fails, requests can be automatically redirected to another server.

In addition, load balancing helps to improve website scalability by allowing additional servers to be added to the server pool as traffic increases. This helps to ensure that the website can handle increased traffic without becoming overloaded and slowing down or crashing.

Web Server:

Once the request reaches the web server, it processes the request and retrieves the relevant data from the database. A web server is a software application that handles incoming requests from clients, such as web browsers, and sends back responses in the form of web pages or other content. When you enter google.com into your browser, your computer sends a request to the website's server, which is typically a web server.

Web servers use the HTTP (Hypertext Transfer Protocol) protocol to communicate with clients. When a client sends a request to a web server, the server responds with an HTTP response, which typically includes a web page or other content, such as images, videos, or scripts.

Web servers can also handle other types of requests, such as file downloads, API calls, or database queries. They can be configured to serve static content, such as HTML or CSS files, or dynamic content, such as content generated by a web application.

Web servers can be either hardware devices or software applications. Popular web server software includes Apache, Microsoft IIS, and my very favorite, Nginx.

Web servers play a critical role in the process of accessing a website. They are responsible for handling incoming requests from clients and sending back responses in the form of web pages or other content. By serving as the backbone of website infrastructure, web servers ensure that website content is delivered quickly and efficiently to users around the world.

Application Server:

The HTML file may contain dynamic content, which is generated by an application server. An application server is a software platform that hosts web applications and provides runtime environments for their execution. When you access google.com, the web server sends requests to the application server to execute the required web applications and generate dynamic content.

The application server is responsible for managing the business logic of web applications, processing user input, and generating dynamic content. It also handles communication with other software components, such as databases, messaging systems, or other web services.

Application servers can support multiple programming languages and frameworks, such as Java, Python, Ruby, or Node.js. They can also provide features such as session management, caching, load balancing, and failover.

Database:

The web server retrieves data from the database and uses it to generate the HTML file. A database is a software application that stores and manages data in an organized and structured way. When you access a website, the website may need to access data stored in a database to display content or perform specific actions.

Databases can be divided into two main categories: relational and non-relational (NoSQL) databases. Relational databases are based on the relational model and use SQL (Structured Query Language) to query and manipulate data. Non-relational databases, on the other hand, use other data models and query languages to store and manage data.

Databases can be hosted on the same server as the web server and application server or on separate servers. In some cases, websites may use multiple databases to store different types of data or to handle different aspects of website functionality. The database contains all the data that Google needs to display on its website, such as search results, advertisements, and user account information.

conclusion:

In conclusion, accessing a website may seem like a simple process, but behind the scenes, a complex series of interactions and processes take place to ensure that content is delivered quickly and securely. From the initial DNS request to the final delivery of content to your browser, each component of website infrastructure plays a critical role in the process of accessing a website.

DNS ensures that your browser can locate the website's IP address, TCP/IP facilitates communication between your browser and the web server, firewalls protect against malicious traffic, HTTPS/SSL encrypts data to ensure secure transmission, load balancers distribute traffic to multiple servers, web servers serve static content, application servers execute dynamic web applications, and databases store and manage data used by web applications.

Understanding the roles of each component in website infrastructure is critical for website developers, IT professionals, and anyone else involved in website maintenance and management. By ensuring that website infrastructure is designed and configured correctly, website owners can improve website performance, scalability, and security, and ensure that website content is delivered quickly and efficiently to users around the world.

Looking at all these steps, how come they happen in less than a second?

Think about that, then search for it!