Systematic Review of Web Server technology – Apache httpd


Abstract
This research looks at a systematic review of Web Server Technologies focusing on Apache httpd. This review focuses on how and why web server applications have been developed and used for different purposes. This has been done by providing a clear explanation of how web servers work and how the apache httpd web server operates. A statistical and historical overview of web servers have been given in order to understand the changes in web and how It has affected the changes in web servers. Also, Apache web server’s features are described and compared to other popular web servers available. Finally, the future of




Introduction
Apache HTTPD is a free and open source, cross platform web server. According to a web server survey, Apache has the largest share of the market of 45.8% and 80 million active sites (Netcraft, 2017).  A web server can be described as a combination of a platform, software and information. It’s a computer with a connection to the internet with a system software which allows the computer to connect to the internet and other systems. The main purpose of a Web server is to deliver content i.e. information to other clients which connects to the server through the use of LAN and WAN. In terms of Apache HTTPD it is an HTTP server daemon which is the software program that runs in the background of a web server. This software waits and listens for incoming network requests, answers the request and automatically serves the hypertext and multimedia objects using HTTP. For example, in a typical web interaction the browser will send an HTTP request to the Web server which listens for requests generally over a TCP port (80). Apache deals with the full HTTP protocol and so it can handle content negotiation authorization. Furthermore, Web stacks contain several components which includes an operating system, web server, database and scripting language. Apache is compatible with different stack models LAMP for Linux, WAMP for Windows and MAMP for Mac.

From this graph, there is a decline of the use of Apache and an increase in popularity of Nginx and this is due to its ability to scale on minimal hardware and its light weight resource utilization. Statistically, Apache weighs in at 46% of sales and a decline of 4% whereas Nginx with 24% market and a 3% growth (Plesky, 2018).











Feature comparison

One of the main reason that Apache is the leading web server in the world is due to its variety of features. There is a large collection of modules that come as part of Apache distribution and the latest version of Apache HTTP server 2.0 has a new module called the Event Multi Processing Module (MPM) which allows more requests to be processed as it allows the server to serve more concurrent requests. Another useful feature Is the customizable error messages where in normal instance a generic error response such as 4xx HTTP status codes will be uninformative whereas customizable error message gives the user a more definitive error. Another important feature is virtual hosting where it allows the hosting of multiple domain names on a single server so that a server can share resources such as memory.  Furthermore, apache supports server side programming languages such as Python, PHP, Perl and TCL. As Apache is open source and scalable, a user can configure to run on a typical home/office PC to a multi CPU server equipped with fast SCSI disks.


Features
Apache httpd
Node.js
NGINX
Redhat JBOSS
Supported OS
Linux, Unix, Windows, Mac OS
Linux, macOS, Windows, Smart OS, FreeBSD and IBM AIX
FreeBSD, Linux, Solaris, AIX, HP-UX, macOS, Windows XP
Linux, Solaris, Windows,
Performance

Good
Excellent for mobile applications
Excellent
Good
Virtual hosting
Yes
Yes – use node-http-proxy as a reverse proxy
No- It has server blocks which is used to encapsulate configuration details
Yes – as the RedHat Web server combines with Apache with a servlet engine.
Server side scripting




Yes
As Node.js is built on server side JavaScript and so Js is primarily used for client side scripting
No- as it is designed as a static and front end proxy. However it supports C plugins as the server is written in C
Default operations on command line interfaces
Open source


Yes
Yes
Yes
No
Caching


Offers a range of caching features such as three-state RFC2616 HTTP caching, value shared object caching and specialised caching
Different modules available such as node_cache or redis cache
Different directives needed such as proxy_cache_path and proxy cache to set up caching
Two different JBOSS cache including Core and POJO versions


Discussion

The main trend that has been identified is to provide a more secure web server without vulnerabilities. As the apache http server powers the majority of webservers in the world, it is critical for the apache foundation to fix any security flaws as quickly as possible. The latest release of Apache httpd 2.4.37 include enhancements such as Run-time Loadable MPM’s, Event MPM, Asynchronous support, pre request configuration sections etc. Additionally, DDOS and web application attacks have risen 14% and 10% respectively. In order to address this, apache modules such as mod_evasive to protect against DoS, DDoS and brute force attacks. In terms of future developments, it would be to address issues such as performance as it Is slower than its rival NGINX. Similarly, it might to implement an event based or asynchronous server instead of a process based server in order to handle requests in few threads.

























References
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