HTML Uniform Resource Locators
HTML Links
When you click on a link in an HTML document, an underlying <a> tag points to a place (an address) on the Web with an href attribute value like this: <a href="lastpage.htm">Last Page</a>.URL - Uniform Resource Locator
Something called a Uniform Resource Locator (URL) is used to address a document (or other data) on the World Wide Web. A full Web address like this: http://www.w3schools.com/html/lastpage.htm follows these syntax rules:scheme://host.domain:port/path/filename
The scheme is defining the type of Internet service. The most common type is http.
The domain is defining the Internet domain name like w3schools.com.The host is defining the domain host. If omitted, the default host for http is www.
The :port is defining the port number at the host. The port number is normally omitted. The default port number for http is 80.
The path is defining a path (a sub directory) at the server. If the path is omitted, the resource (the document) must be located at the root directory of the Web site.
The filename is defining the name of a document. The default filename might be default.asp, or index.html or something else depending on the settings of the Web server.
WebServer
It is a software to manage webpages, this provides security for webpages[security for filesystem] and supports server side code execution.
Webserver will receive http request and provides httpresponse, hence it is called “HTTP SERVER”.
- apache webserver[oldest web server]
- java webserver
- IIS [Internet Information Services]—provided by Microsoft
ASP.NET towards windows requires IIS5.0 or later
ASP.NET towards linux requires Apache webserver
http://localhost ---> if it is personal pc
http://servername ---> if IIS is running in remote location[network environment]
Protocol
It is a set of rules which need to be followed while transferring the data over the network for communication. Browser and WebPages will communicate based on http rules [hyper text transfer protocol]
Protocol
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Low-level protocol High-level protocol
[tcp/ip] Http,Https,SOAP,TDS,SMTP
[State-Full] [State-Less]
http-request
C#.net------oracle asp.net-----------server
http-response
Go-Get-Maintain Go-Get-Forget
1) To work with mails SMTP [simple mail transfer protocol] is required.
2) Network is a collection of the computers which are connected together by using a protocol.
3) When IIS Server installed then FTP and SMTP protocols also will be installed by default.
4) HTTP is stateless protocol, the stateless nature is considered as an advantage, it will reduce burden on webserver this will improve performance of webserver.
Website
It is an application managed by webserver; each website will maintain a link to physical path of WebPages. Webserver can maintain different websites; each website is identified by a unique number called Port Number. The client communication to website is based on port number. The default port number for http is 80[i.e. http request without port number will be connected to website with port number 80].
Notes:-
n Scheme is a protocol
n Host is a server name where websites are stored [ex www]
n Domain is a unique name provided to a single website.
n Port No. is provided uniquely to each website.
n Each website is a virtual directory which maintains WebPages.
