What happens when you type in www.google.com in your browser and press Enter
Some steps occur from when you hit enter to when you get that familiar google homepage that lets you search whatever you want. They are;
1 DNS Lookup
2 Connection
3 HTTP and HTTPS
4 Firewall
5 Load Balancer
6 Webserver
7 Application Server
8 Database
https://(protocol) www(sub-domain) .google(domain) .com(root) /toys-for-us(path)
Here are the steps in detail…
DNS Lookup
Immediately after hitting enter, the browser sends a request to the domain name system server that returns the IP address of the domain name.
There is a lot more steps in that process that happens in the blink of an eye
- The computer/browser checks its A record (A for Address) to find the ip address of www.google.com. An A record can be simply described as a table mapping domain names to ip addresses. Websites and webpages are served from a server, these servers are identified by their ip addresses. IP addresses are a unique address that identifies a device on the internet.They are a pain to remember as they are just series of digits or letters (Like 216.58.223.196 — IPv4 or 2001:db8:0:1234:0:567:8:1 - IPv6) so we use domain names instead (Like google.com)
- If the IP address is not in the browser’s memory, the request goes through these points.
Browser => Operating system => Resolver => Root => Top Level Domain name servers => IP address
Resolver — Your ISP knows the root (.com, .net, .tech, .org)
Root — Knows the Top level domain name servers ([a-m].gtld-servers.net)
TLD Authoritative name servers — know all domain names that use the root (.com) and returns the IP address of the domain name.
Connection (TCP/IP)
Transmission Control Protocol (TCP) and Internet Protocol (IP) are used to establish a connection between the client and the server hosting the site/application. On some browsers, you’ve probably seen the “Performing TLS handshake” text while a page is loading. The TLS handshake happens when a client sends a request and the server acknowledges the request for a connection After the acknowledgement is sent, the browser then sends the request for the homepage of google.
Then the server sends the html code and any other resources (scripts, images or videos) necessary to display the homepage on the browser over http or https.
Firewall
This monitors outgoing and incoming traffic based on rules (like port restrictions, or specific protocols usage) Some firewalls also check data sent for malwares.
Load Balancer
Servers will now be broken down to load balancers and webservers (although some webservers have their own load balancers).
Load balancers are used to share traffic/requests between backend webservers. One popular load balancer software is HA Proxy. It can use different methods for load balancing between webservers such as round-robin, leastconn, ratioed round-robin.
Web Server
Webservers serve the static web content to the browsers load is shared between multiple webservers by the load balancer(s).
Application server
The application server are used when there is a need for dynamic web content on a website/webpage or for web applications that require real-time operations like E-commerce websites.
Database
Databases for applications or dynamic content need to be stored, one way of storing is through relational databases that use persistent storage and can perform CRUD operations (create, read, update, delete). The application server requests some data from the google database to use in its response.
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