World wide web has become one of the most prevalent things in our modern society.The amount of traffic traveling over the web every day is staggering.Each and every one of us probably use the web daily for communication,research and fun, but the vast majority have no idea how it all works.
In this post ,we aim to describe how web server like google,yahoo,etc work,and how attacker can find vulnerabilities or loopholes in them.So first we are trying to know actually what is a web server.
What Is A Web Server?
A sever is a computer system that provide certain service like mail,website etc.The web server is a computer system which specifically provides web server to serve the web pages.This service typically listen on port 80 (http) or port 443 (https) .although often times web server can be configured to run on non standard ports like 8888,8080 etc.Microsoft's internet information server and Apache are the most common example of web servers,other web server include macro- httpd.
A web server is a program that,using the client/server model and the www's HyperText Transfer Protocol (HTTP),serves the file that for web pages to web user (whose computer contains http clients and forward their requests) Every computer on the internet that contains a web site have a web server program.Two leading web server are Apache,The most widely installed web server,and Microsof's internet information server (IIS).
Other web server include Novell's web server for user of its Netware operating system and IBM'S family of Lotus Domino servers,primarily for IBM'S OS/390 and AS/400 costumers.
Web server often come as part of a larger package of internet and internet related programs for serving email, downloading requests for file transfer Protocol (FTP) files,and building and publishing web pages.Consideration in choosing a web server include how well it work with the operating system and other servers,its ability to handle server side programming,security characteristics,and publishing,search engine,and site building tools that may comes with it.
A web server is the combination of computer and the program installed on it.Web servers interact with the client through web browser.It delivers the web pages to the client and to an application by using the web browser and HTPP protocols respectively.We can also define the web server as the package of large number of program installed on a computer connected to internet or internet for downloading the re quests file using FTP,serving email and building and publishing web pages.A web server works on a client server model.A computer connected to the internet or internet must have a server program.While talking about java language then web serer is a server that is used to support the web component like the server and JSP.
A computer connected to the internet for providing the services to a small company or a departmental store may contains the http server (To access and store the web pages and files) ,SMTP sever(to support mail services) FTP server (for files downloading) and NNTP server (for news group) .The computer containing all the above servers is called the web server.Internet service provider and the large companies may have all the servers like HTTP server,SMTP server,FTP server an many more on separate machine. In case of java,a web server can be defined as the server that only support to the web component like servlet and jsp.Notice that it does not support to the business component like EJB.
Working Of A Server With Example
At the most basic level possible,there are mainly three processes which are given below.
1. Creating connection between server and browser.
2. Request from browser to server.
3. Response from server
Example of basic working given in below steps.
Suppose you visit a page from web browser http://www.abc.com/web-server.html
Step:1) The browser broke the url into three parts:
* The protocol (http)
* The server name (www.abc.com)
* The file name (web-server.html)
Step:2) The web browser communicated with a name server (DNS server=Domain name system server) to translate the server name into IP address,which is uses to connect to the server machine.
Step:3) The browser then formed a connection to the server at that ip address on port 80.
Step:4) following the http protocol,the browser sent a GET request to the server,asking for the file "http://www.abc.com/web-server.html" (Note that cookie may be sent from browser to the server with the GET request.
Step:5) The server then sent the HTML text for the web page to browser.(cookie may also be sent from server to browser in the header for the page.)
Step:6) The browser read the HTML tags and formatted the page onto your screen.
So my dear friends this is the actuall process of web server's working,if you have any question related on this topic please mail me ,I will try to solve your query with in a hour.Thanks for reading it carefully.