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Introduction

We are using the internet every day and we visit a lot of websites but surely you've got ever used the web and asked how it works what exactly happens in the backend when you visit a site in this post I will explain what the web is and the way it works during a simple way for?all people without the necessity for a degree in areas associated with technology can know it .

How does the Internet work? The Internet's growth has become explosive and it seems impossible to escape the bombardment of?www.com's seen constantly on television, heard on the radio, and seen in magazines. Because the Internet has become such a large part of our lives, a good understanding is needed to use this new tool most effectively.

Where to Begin? Internet Addresses

Because the Internet is a global network of computers each computer connected to the Internet?must?have a unique address. Internet addresses are in the form?nnn.nnn.nnn.nnn?where nnn must be a number from 0 - 255. This address is known as an IP address. (IP stands for Internet Protocol; more on this later.)

The picture below illustrates two computers connected to the Internet; your computer with IP address 1.2.3.4 and another computer with IP address 5.6.7.8. The Internet is represented as an abstract object in-between. (As this paper progresses, the Internet portion of Diagram 1 will be explained and redrawn several times as the details of the Internet are exposed.)

If you connect to the Internet through an Internet Service Provider (ISP), you are usually assigned a temporary IP address for the duration of your dial-in session. If you connect to the Internet from a local area network (LAN) your computer might have a permanent IP address or it might obtain a temporary one from a DHCP (Dynamic Host Configuration Protocol) server. In any case, if you are connected to the Internet, your computer has a unique IP address.

What is DNS and How does it work?

The Domain Name System (DNS) is the phonebook of the Internet. Humans access information online through domain names, like nytimes.com or espn.com. Web browsers interact through Internet Protocol (IP) addresses. DNS translates domain names to IP addresses so browsers can load Internet resources.

Each device connected to the Internet has a unique IP address which other machines use to find the device. DNS servers eliminate the need for humans to memorize IP addresses such as 192.168.1.1 (in IPv4), or more complex newer alphanumeric IP addresses such as 2400:cb00:2048:1::c629:d7a2 (in IPv6).

What are IP & TCP?

The Internet Protocol (IP) is the address system of the Internet and has the core function of delivering packets of information from a source device to a target device. IP is the primary way in which network connections are made, and it establishes the basis of the Internet. IP does not handle packet ordering or error checking. Such functionality requires another protocol, typically TCP.

The TCP/IP relationship is similar to sending someone a message written on a puzzle through the mail. The message is written down and the puzzle is broken into pieces. Each piece then can travel through a different postal route, some of which take longer than others. When the puzzle pieces arrive after traversing their different paths, the pieces may be out of order. The Internet Protocol makes sure the pieces arrive at their destination address. The TCP protocol can be thought of as the puzzle assembler on the other side who puts the pieces together in the right order, asks for missing pieces to be resent, and lets the sender know the puzzle has been received. TCP maintains the connection with the sender from before the first puzzle piece is sent to after the final piece is sent.

IP is a connectionless protocol, which means that each unit of data is individually addressed and routed from the source device to the target device, and the target does not send an acknowledgement back to the source. That’s where protocols such as the Transmission Control Protocol (TCP) come in. TCP is used in conjunction with IP in order to maintain a connection between the sender and the target and to ensure packet order.

For example, when an email is sent over TCP, a connection is established and a 3-way handshake is made. First, the source send an SYN “initial request” packet to the target server in order to start the dialogue. Then the target server then sends a SYN-ACK packet to agree to the process. Lastly, the source sends an ACK packet to the target to confirm the process, after which the message contents can be sent. The email message is ultimately broken down into packets before each packet is sent out into the Internet, where it traverses a series of gateways before arriving at the target device where the group of packets are reassembled by TCP into the original contents of the email.

What Is a Firewall?

A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules.

Firewalls have been a first line of defense in network security for over 25 years. They establish a barrier between secured and controlled internal networks that can be trusted and untrusted outside networks, such as the Internet.?

A firewall can be hardware, software, or both.

What is HTTPS?

HTTPS (Hypertext Transfer Protocol Secure) is a secure version of the HTTP protocol that uses the SSL/TLS protocol for encryption and authentication. HTTPS is specified by RFC 2818 (May 2000) and uses port 443 by default instead of HTTP’s port 80.

The HTTPS protocol makes it possible for website users to transmit sensitive data such as credit card numbers, banking information, and login credentials securely over the internet. For this reason, HTTPS is especially important for securing online activities such as shopping, banking, and remote work. However, HTTPS is quickly becoming the standard protocol for?all?websites, whether or not they exchange sensitive data with users.

How is HTTPS different from HTTP?

HTTPS adds?encryption,?authentication, and?integrity?to the HTTP protocol:

Encryption: Because HTTP was originally designed as a clear text protocol, it is vulnerable to eavesdropping and man in the middle attacks. By including SSL/TLS encryption, HTTPS prevents data sent over the internet from being intercepted and read by a third party. Through public-key cryptography and the SSL/TLS handshake, an encrypted communication session can be securely set up between two parties who have never met in person (e.g. a web server and browser) via the creation of a shared secret key.

Authentication: Unlike HTTP, HTTPS includes robust authentication via the SSL/TLS protocol. A website’s SSL/TLS certificate includes a public key that a web browser can use to confirm that documents sent by the server (such as HTML pages) have been digitally signed by someone in possession of the corresponding private key. If the server’s certificate has been signed by a publicly trusted certificate authority (CA), such as SSL.com, the browser will accept that any identifying information included in the certificate has been validated by a trusted third party.

HTTPS websites can also be configured for mutual authentication, in which a web browser presents a client certificate identifying the user. Mutual authentication is useful for situations such as remote work, where it is desirable to include multi-factor authentication, reducing the risk of phishing or other attacks involving credential theft. For more information on configuring client certificates in web browsers, please read this how-to.

Integrity: Each document (such as a web page, image, or JavaScript file) sent to a browser by an HTTPS web server includes a digital signature that a web browser can use to determine that the document has not been altered by a third party or otherwise corrupted while in transit. The server calculates a cryptographic hash of the document’s contents, included with its digital certificate, which the browser can independently calculate to prove that the document’s integrity is intact.

What Is Load Balancing?

Load balancing?refers to efficiently distributing incoming network traffic across a group of backend servers, also known as a?server farm?or?server pool.

Modern high?traffic websites must serve hundreds of thousands, if not millions, of concurrent requests from users or clients and return the correct text, images, video, or application data, all in a fast and reliable manner. To cost?effectively scale to meet these high volumes, modern computing best practice generally requires adding more servers.

A load balancer acts as the “traffic cop” sitting in front of your servers and routing client requests across all servers capable of fulfilling those requests in a manner that maximizes speed and capacity utilization and ensures that no one server is overworked, which could degrade performance. If a single server goes down, the load balancer redirects traffic to the remaining online servers. When a new server is added to the server group, the load balancer automatically starts to send requests to it.

In this manner, a load balancer performs the following functions:

• Distributes client requests or network load efficiently across multiple servers
• Ensures high availability and reliability by sending requests only to servers that are online
• Provides the flexibility to add or subtract servers as demand dictates

What Is an Application Server vs. a Web Server?

Despite the contrast implied by “application server vs. web server,” on the Internet the two types of server are usually deployed together for a common purpose: fulfilling user requests for content from a website. There are no standards documents that define the properties of web servers and application servers, but let’s look at how the terms are commonly understood.

A web server‘s fundamental job is to accept and fulfill requests from clients for static content from a website (HTML pages, files, images, video, and so on). The client is almost always a browser or mobile application and the request takes the form of a Hypertext Transfer Protocol (HTTP) message, as does the web server’s response.

An application server’s fundamental job is to provide its clients with access to what is commonly called business logic, which generates dynamic content; that is, it’s code that transforms data to provide the specialized functionality offered by a business, service, or application. An application server’s clients are often applications themselves, and can include web servers and other application servers. Communication between the application server and its clients might take the form of HTTP messages, but that is not required as it is for communication between web servers and their clients. Many other protocols are popular, including the variants of CGI.

What is Database?

A database is a systematic collection of data. They support electronic storage and manipulation of data. Databases make data management easy.

Let us discuss a database example: An online telephone directory uses a database to store data of people, phone numbers, and other contact details. Your electricity service provider uses a database to manage billing, client-related issues, handle fault data, etc.

Let us also consider Facebook. It needs to store, manipulate, and present data related to members, their friends, member activities, messages, advertisements, and a lot more. We can provide a countless number of examples for the usage of databases.

Distributed databases:

A distributed database is a type of database that has contributions from the common database and information captured by local computers. In this type of database system, the data is not in one place and is distributed at various organizations.

Relational databases:

This type of database defines database relationships in the form of tables. It is also called Relational DBMS, which is the most popular DBMS type in the market. Database example of the RDBMS system include MySQL, Oracle, and Microsoft SQL Server database.

Object-oriented databases:

This type of computers database supports the storage of all data types. The data is stored in the form of objects. The objects to be held in the database have attributes and methods that define what to do with the data. PostgreSQL is an example of an object-oriented relational DBMS.

Centralized database:

It is a centralized location, and users from different backgrounds can access this data. This type of computers databases store application procedures that help users access the data even from a remote location.

Open-source databases:

This kind of database stored information related to operations. It is mainly used in the field of marketing, employee relations, customer service, of databases.

Cloud databases:

A cloud database is a database which is optimized or built for such a virtualized environment. There are so many advantages of a cloud database, some of which can pay for storage capacity and bandwidth. It also offers scalability on-demand, along with high availability.

Data warehouses:

Data Warehouse is to facilitate a single version of truth for a company for decision making and forecasting. A Data warehouse is an information system that contains historical and commutative data from single or multiple sources. Data Warehouse concept simplifies the reporting and analysis process of the organization.

NoSQL databases:

NoSQL database is used for large sets of distributed data. There are a few big data performance problems that are effectively handled by relational databases. This type of computers database is very efficient in analyzing large-size unstructured data.