A web server is an Internet server that responds to HTTP requests to deliver content, files and pages. Servers are the key to any web hosting. Without a web server, you cannot even show your website online.
A page can be viewed on the Internet when the browser requests it from the web server and the web server responds with that page.
1. The web browser requests a specific web page - looking for the right IP address associated with that domain.
2. The web browser requests a full URL from server after knowing the IP.
3. The web server finds and collect all the information – including things like dynamic elements, content and responds to the browser by sending the desired pages. And send error message if page doesn't exist.
4. Web browser receives this complete page and displays it on screen.
Nginx is an open-source web server, known for its easy configuration, stability and performance. This server was created by Igor Sysoev and publicly released in 2004. It is very popular with 39% approx. market share, used by many big companies like Facebook, Twitter, Apple, NASA, Netflix, IBM, Google and many more.
Since its initial success as a web server, it is now also used as a reverse proxy, HTTP cache, and load balancer.
Apache is of the world's most popular web servers developed by the Apache Software Foundation with around 45% of market. One of the oldest server launched in 1995. Apache is an open source server that supports almost all operating systems including Linux, Unix, Windows, FreeBSD, Mac OS X and more.
Easy to install on multiple platforms and highly stable server compared to others. It use modular structure you can also customize apache server.
IIS web server is developed by Microsoft. It hosts websites, web applications and services required by users or developers. Typically, IIS is used to host ASP.NET web applications and static websites. It can also be used as an FTP server.
This server has all the features like other servers. But this is not an open source and is not much easier when adding individual modules and modification becomes a bit tricky.
Litespeed (LSWS) is a high-performance Apache drop-in replacement from Litespeed technologies. LSWS is the 4th most popular web server on the Internet. It can be used to change an existing Apache server without changing the details of another program or operating system.
Lightspeed is faster than Apache when serving PHP content. It is an ideal hosting platform to serve WordPress, Drupal and Joomla based websites.