A proxy server shares one internet connection with ALL the computers on your local network or it is a computer that offers a computer network service to allow clients to make indirect network connections to other network services. So basically a proxy (proxy server) is a server that acts as mediator between the client (the computer of a user) and server (the computer on the other ends of network connection on which the information requested by the user appears for example web server site.) When clients request data from an Internet resource,traffic goes from your web browser/application first through the proxy before it reaches the requested sources and back through the proxy then the proxy will transmit the data to you.

A proxy server sits between a client application, such as a Web browser, and a real server. It intercepts all requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request to the real server.

Do not confuse a proxy server with a NAT (Network Address Translation). Although they appear to be very similar, a proxy server actually does the work of connecting to, responding to, and receiving traffic from the Internet. In other words, it acts on behalf of the client computer. A NAT, on the other hand, merely changes the origination address of traffic coming through it and passes it to the Internet. The computer behind the NAT,not the NAT itself, does the work. The NAT is intended to be transparent to the whole process.
For those who understand the OSI (Open System Interconnection) model of networking,the technical difference between a proxy and a NAT is that the proxy server works on the transport layer (layer 4), or higher of the OSI model, whereas a NAT works on the network layer (layer 3).
How Proxy Servers Work :

1. When a computer on the intranet makes a request out to the Internet-such as to retrieve a Web page from a Web server-the internal computer actually contacts the proxy server, which in turn contacts the Internet server. The Internet server sends the Web page to the proxy server, which then forwards the page to the computer on the intranet.

2. Proxy servers log all traffic between the Internet and the intranet. For example, a Telnet proxy server could track every single keystroke hit in every Telnet session on the intranet-and could also track how the external server on the Internet reacts to those keystrokes. Proxy servers can log every IP address, date and time of access, URL, number of bytes downloaded, and so on. This information can be used to analyze any attacks launched against the network. It can also help intranet administrators build better access and services for employees.

3. Some proxy servers must work with special proxy clients. A more popular approach is to use off-the-shelf clients such as Netscape with proxy servers. When such an off-the-shelf package is used, it must be specially configured to work with proxy servers from a configuration menu. Then the intranet employee uses the client software as usual. The client software knows to go out to a proxy server to get the data, instead of to the Internet.

4. Proxy servers can do more than relay requests back and forth between an intranet and the Internet. They can also implement security schemes. For example, an FTP proxy server could be set up to allow files to be sent from the Internet to a computer on the intranet,but to block files from being sent from the corporate network out to the Internet-or vice versa. In this way, intranet administrators can block anyone outside the corporation from downloading vital corporate data. Or they can stop intranet users from downloading files which may contain viruses.

5. Proxy servers can also be used to speed up the performance of some Internet services by caching data-keeping copies of the requested data. For example, a Web proxy server could cache many Web pages, so that whenever someone from the intranet wanted to get one of those Web pages, they could get it directly from the proxy server across high-speed intranet lines,instead of having to go out across the Internet and get the page at a lower speed from Internet lines.

The different types of Proxy Servers :

There are many different types of Proxy Servers out there. Depending on the purpose you can get Proxy Servers to route any of these common protocols, and many more ;
1)FTP Proxy Server:

Relays and caches FTP Traffic.

2)HTTP Proxy Server:

A one way request to retrieve Web Pages.

3)Socks Proxy Server:

A newer protocol to allow relaying of far more different types of data, whether TCP or UDP.

4)NAT Proxy Server:

This one works a little different, it allows the redirection of all packets without a Program having to support a Proxy Server.

5)SSL Proxy Server:

An extension was created to the HTTP Proxy Server which allows relaying of TCP data similar to a Socks Proxy Server. This one done mainly to allow encryption of Web Page
requests.

Furthermore, a Proxy Server can be split into another two Categories:

1)Anonymous:

An Anonymous Proxy Server blocks the remote Computer from knowing the identity of the
Computer using the Proxy Server to make requests.

2)Transparent:

A Transparent Proxy Server tells the remote Computer the IP Address of your Computer.
This provides no privacy.

Anonymous Proxy Servers can further be broken down into two more categories, Elite and Disguised. An Elite Proxy Server is not identifiable to the remote computer as a Proxy in any way. A Disguised Proxy Server gives the remote computer enough information to let it know that it is a Proxy, however it still does not give away the IP of the Computer it is relaying information for.

One of the most important factors considered while choosing a web host is the control panel. The host may come come up with lots of disk space, bandwidth and also good uptime but it is worthless if it has a bad control panel. Many webhosts have their own custom built control panels to stand out from the crowd. But a majority of clients had faced problems with navigating that control panel.

Always look for control panels used by the hosting company before selecting a hosting package. The most widely used control panel nowadays is “Cpanel”.

It is the most easy and helpful control panel if you are switching your web site from one host to another. If both the hosts uses Cpanel then it’s easier to transfer a website by clicking on export/import buttons. There might be lot of problems faced if the control panels used are different.

There are other control panels as well which still have good features and are very easy to use, but still “Cpanel” is the best so far.

Check out Cpanel Hosting by eUKhost

AJAX (Asynchronous JavaScript and XML) is the hot and happening new web technology.
When AJAX was introduced last year, it became popular quickly bcoz of its powerful functionality of executing server side scripting and dynamically replacing document contents without actually reloading the current document.
But now developers are busy in finding solutions to AJAX functionality as there are some problems with AJAX and AJAX accessibility.

Even if a user is expecting information to update, they might not notice the actual change in data. In addition, since pages are updated incrementally, AJAX applications may not have distinct uniform resource identifiers (URIs) that can be bookmarked. This can also lead to issues with the Back button not functioning as expected.

JavaScript is only meant for enhancing behavior and performing client-side manipulations. It was never meant to handle complex business logic or hefty calculations. So, you have to split business logic between your server-side code and a client-side script file. Another possible problem is potentially having to duplicate logic in both your server-side code and your client-side scripts.

AJAX will not work in all web browsers. As its name suggests, AJAX requires JavaScript. This alone means that AJAX applications will not work in web browsers and devices that do not support JavaScript. For this reason it is not accessible to many typical Web users.

The current solution to these problems is to either provide a non-AJAX alternative to your application or to allow your AJAX application to continue to function if JavaScript and XMLHttpRequest are not supported. The general strategy here is to start by creating a page that works like a normal site-processing information on page loads and refreshes. Then, if JavaScript is enabled, we have our scripts bypass this normal functionality and replace it with sweet Ajax functionality.

Windows Script Host (WSH), can be thought of in the same way as old DOS batch files,
because it allows you to directly script and automate parts of the core operating
system using plain text files. By using these scripts you can automate anything from
the Windows registry, through to files and shortcuts,through to network printers and
shares, and because of the extensible nature of the language there is practically no
limit to what it can do.
WSH is really made up of three main components:

-The core host that ties all the pieces together.
-The scripting engines that provides the scripting languages, such as VBScript,
JScript and PerlScript.
-The Scripting Hosts that actually execute the scripts, two are shipped as standard
WSCRIPT.EXE [a Windows GUI version] and CSCRIPT.EXE [a text mode command-line version].

The advantage of the Windows Script File (.WSF) is that it allows you to use a combination of scripting languages within a single file.

A collection of scripts for automating certain tasks.So if anyone wants to jump straight to creating and using the script, you can simply type it in and save it as a file. For those hungry for detail, we’ll be explaining each script as it comes. Hopefully, this should be help enough for you to start writing your own scripts.About the only thing you will need to create and run the scripts is the trusty Notepad. Enter the script text and save the file with a .vbs extension. Whenever you want to use the script, simply double-click the file to execute your script. That said, let’s get down to the scripts.

Examples :

Scripts alone can be so powerful that one can even create viruses using it: the dreaded ‘ILOVEYOU’ virus is, at its core, just a text file containing a script. Don’t despair-creating and executing scripts in Windows doesn’t require you to install any software or compile any¬thing; instead, it requires code-a lot of code. OK. despair a bit, but in the end it’ll be worth it.

1) Delete files :

You probably saw this coming after the last one: you can use the “deletefile” object to delete any files.
This is useful when you want to make sure that cer¬tain cm:ectories are empty or certain files are deleted
before you shut down Wmdows, or simply to clear out all tem¬porary files.

The script is like ;

SetFSO= CreateObject(”Scripting.FileSystemObjec t”)
FSODeleteFile “C:\testl \temp.doc”
Rather self~lanatory. You’re already familiar with the first part by now; the next line has an easy to understand function, “FSO.DeleteFile”, fol¬lowed by the path to the folder or file you want to delete.
If you want to nuke the entire directory, use the … variable to include all files in the directory specified in the script.

2) Map a network drive using a shortcut :

Ever wanted a simple shortcut to map your network shares to a drive? You can do so using this script.Remember that you can also add as many drives you want to map, similar to WSHShell.Run

Here it is ;

Set WSHNetwork = WScript.CreateObject(”WScript.Network”)

WSHNetwork.MapNetworkDrive”5:”, “\ \network\share 1″

WSHNetwork.MapNetworkDrive-r:”, “\ \network\share 2″

WSHNetwork.MapNetworkDrive”U:”, “\ \network 2\share 3″

Again, the first line asks WSH to declare the “WSHNetwork” object. As mentioned before, since we are making changes to the network subsystem-a network drive in this case-we’ll need to declare it, like we have done in the first line. Further down, we see “WSHNetwork” using the “MapNetworkDrive” function, this is the actual command for creating a network drive. Take note that the drives them selves are in their own set of quotes followed by the network shares. Similar to the Run function earlier, the drives will be mapped in order from top to bottom.

On 20th January 2007 it was released worldwide to the general public.
Windows vista conatins hundreds of new features..
1)The most significant is an updated Graphical User Interface(GUI)..
2)Improved in searching features.
3)Windows DVD marker like new multimedia creation tools.
4)Vista also aims to increase the level of communication using peer-to-peer technology.
5)For developers,Vista includes version 3.0 of the .NET Framework which is easier to write high quality applications than with the Windows API.
6)Windows Vista Ultimate also enables you to easily recover previous versions of files and documents that have been accidentally changed.
7)It has new self-healing technology…Windows Vista Ultimate can automatically identify and fix problems as they occur.
8)You can use Complete PC Backup and Complete PC Restore to get entire PC backup

Iframes, or inline frames, allow you to load html files into an existing document. Frames are inline frames that are sometimes referred to as floating frames. One of the main advantages of the iframe tag is that it can be used to load external html or xhtml pages into the current document without distrubing the original page.

This iframe tag was not much popular when introduced because it was not supported by all the major browsers. But now Internet Explorer 4+, Netscape 6+, Firefox, Mozilla, Opera and other modern browsers all support iframes.

A basic iframe tag is :

<iframe></iframe>

However iframe supports a number of attributes like :

src, name, width, height, align, frameborder, scrolling

New html documents can be loaded into the iframe without disrupting the rest of the document. CSS and JavaScript can be used to manipulate properties of the iframe, such as its position and size. JavaScript can also be used to communicate between the document containing the iframe and the document loaded inside it.
So, dynamically the iframe contents can be replaced.

Also the iframes can be kept hidden. the hidden iframes can execute the code and then can send the results to the main document containing it using javascript. Thus, hidden iframes can be used as an alternative ti AJAX. Now-a-days many developers find it easy to use iframes for remote scripting. Remote Scripting is the process by which a client-side application running in the browser and a server-side application can exchange data without reloading the page.