What happens when you type https://www.google.com in your browser.
This is a very layman description of what happens in the back end. I tried not to use any big technical jargons
As soon as we enter the web address name (Google) in our browser and press enter the browser will send this web address name (Domain name) to the ISP(internet service provider like airtel , hatway etc) asking for the IP address of the webpage.
Step1 : DNS request ?
A DNS query (also known as a DNS request) is a demand for information sent from a user’s computer (DNS client) to a DNS server. In most cases a DNS request is sent, to ask for the IP address associated with a domain name. An attempt to reach a domain, is actually a DNS client querying the DNS servers to get the IP address, related to that domain. In general, there are two ways of resolving a host or a domain name to an IP address, using the domain name system — a Recursive query and a non-Recursive query. The Recursive query is, when a DNS client directly gets the IP address of a domain, by asking the name server system to perform the complete translation.The non-Recursive query is, when a DNS client contacts the name servers, one by one, until it finds the server, containing the needed information.
How it works?
The process behind Recursive queries, can be explained by the following example:
1. A user opens up his favorite browser and enters https://www.google.com in the address bar. His computer does not know the IP address for www.google.com, so it sends a request to the user’s DNS resolver.
2. The resolver does not know the IP address for www.google.com, so it will query one of the root DNS servers. The root servers know the locations of all the TLDs, such as .com, they do not know the IP of www.google.com, so they return the location of the .com servers.
4. Once the query reaches the .com TLD servers, it will find the Authoritative DNS server of www.google.com and will reply to the resolver with that server.
5. The resolver will send a query to the Authoritative DNS server of the domain and will resolve it.
6. The Authoritative DNS server of the domain will check within its database and will find an entry for www.google.com, which has an IP address.
7. Finally the resolver will know the IP address for www.google.com , so our web browser is ready to go The communication between the browser and server occurs over what is referred to as Transmission Control Protocol/Internet Protocol (TCP/IP). This communication protocol is not mandatory — any working protocol goes — but is a standard when it comes to web infrastructure and the OSI model.
Step2 : TCP/IP
TCP/IP stands for Transmission Control Protocol/Internet Protocol and is a suite of communication protocols used to interconnect network devices on the internet. TCP/IP is also used as a communications protocol in a private computer network (an intranet or extranet).
The entire IP suite — a set of rules and procedures — is commonly referred to as TCP/IP. TCP and IP are the two main protocols, though others are included in the suite. The TCP/IP protocol suite functions as an abstraction layer between internet applications and the routing and switching fabric
How does TCP/IP work?
TCP/IP uses the client-server model of communication in which a user or machine (a client) is provided a service, like sending a webpage, by another computer (a server) in the network.
Collectively, the TCP/IP suite of protocols is classified as stateless, which means each client request is considered new because it is unrelated to previous requests. Being stateless frees up network paths so they can be used continuously.
The transport layer itself, however, is stateful. It transmits a single message, and its connection remains in place until all the packets in a message have been received and reassembled at the destination.
The TCP/IP model differs slightly from the seven-layer Open Systems Interconnection (OSI) networking model designed after it. The OSI reference model defines how applications can communicate over a network. . All TCP/IP Communication are filtred by Firewall.
Step3 : Firewall
A Firewall is a network security device that monitors and filters incoming and outgoing network traffic based on an organization’s previously established security policies. At its most basic, a firewall is essentially the barrier that sits between a private internal network and the public Internet. A firewall’s main purpose is to allow non-threatening traffic in and to keep dangerous traffic out.
What Firewalls Do?
A Firewall is a necessary part of any security architecture and takes the guesswork out of host level protections and entrusts them to your network security device. Firewalls, and especially Next Generation Firewalls, focus on blocking malware and application-layer attacks, along with an integrated intrusion prevention system (IPS), these Next Generation Firewalls can react quickly and seamlessly to detect and react to outside attacks across the whole network. They can set policies to better defend your network and carry out quick assessments to detect invasive or suspicious activity, like malware, and shut it down.
Step3 : HTTPS/SSL
SSL stands for Secure Sockets Layer and, in short, it’s the standard technology for keeping an internet connection secure and safeguarding any sensitive data that is being sent between two systems, preventing criminals from reading and modifying any information transferred, including potential personal details. The two systems can be a server and a client (for example, a shopping website and browser) or server to server (for example, an application with personal identifiable information or with payroll information).
It does this by making sure that any data transferred between users and sites, or between two systems remain impossible to read. It uses encryption algorithms to scramble data in transit, preventing hackers from reading it as it is sent over the connection. This information could be anything sensitive or personal which can include credit card numbers and other financial information, names and addresses.
TLS (Transport Layer Security) is just an updated, more secure, version of SSL. We still refer to our security certificates as SSL because it is a more commonly used term, but when you are buying SSL from DigiCert you are actually buying the most up to date TLS certificates with the option of ECC, RSA or DSA encryption.
HTTPS (Hyper Text Transfer Protocol Secure) appears in the URL when a website is secured by an SSL certificate. The details of the certificate, including the issuing authority and the corporate name of the website owner, can be viewed by clicking on the lock symbol on the browser bar.
Step3 : LOADBALANCE
Throughout these first five steps I’ve repeatedly referenced our browser as communicating with the server hosting www.google.com. Now, I was not [intentionally] misleading you, I promise, but the truth is, up to this point, we haven’t quite yet interacted with the server hosting our desired web page. Instead, we’ve been interacting with an initial in-between — the load balancer.
To introduce the importance of load balancing, realize that over four billlion people use the internet today. Think about the number of HTTP GET requests sent to a particular website every day, every hour, every minute, and every second, especially for those behemoth websites such as Google or Amazon. Then think about how your personal computer begins to slow down after running just a handful of processes, let alone if it had to manage over 63,000 requests per second.
Step3 : Web server
A web server is software and hardware that uses HTTP (Hypertext Transfer Protocol) and other protocols to respond to client requests made over the World Wide Web. The main job of a web server is to display website content through storing, processing and delivering webpages to users.
Step4 : Application server
An application server is a modern form of platform middleware. It is system software that resides between the operating system (OS) on one side, the external resources (such as a database management system [DBMS], communications and Internet services) on another side and the users’ applications on the third side.
Step4: Database
A database is an organized collection of structured information, or data, typically stored electronically in a computer system. A database is usually controlled by a database management system (DBMS).
Resources:
♦ https://www.quora.com/What-will-happen-in-backend-when-we-type-Google-com-in-url
♦ https://www.techtarget.com/searchnetworking/definition/TCP-IP
♦ https://www.cloudns.net/wiki/article/254/
♦ https://www.checkpoint.com/cyber-hub/network-security/what-is-firewall/
♦ https://www.websecurity.digicert.com/security-topics/what-is-ssl-tls-https
♦ https://www.techtarget.com/whatis/definition/Web-server
♦ https://www.gartner.com/en/information-technology/glossary/application-server
♦ https://www.oracle.com/database/what-is-database/
