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CIDR is the standard that specifies the details of both classless addressing and an associated routing scheme. Accordingly, the name is slightly inaccurate designation because CIDR specifies addressing as well as routing. The original IPv4 model built on network classes was a useful mechanism for allocating identifiers (netid and hostid) when the primary users of the Internet were academic and research organisations. But, this mode proved insufficiently flexible and inefficient as the Internet grew rapidly to include gateways into corporate enterprises with complex networks. By September 1993, it was clear that the growth in Internet users would require an interim solution while the details of IPv6 were being finalised. The resulting proposal
was submitted as RFC 1519 titled ‘Classless Inter-Domain Routing (CIDR): an Address Assignment and Aggregation Strategy.’ CIDR is classless, representing a move away fromthe original IPv4 network class model. CIDR is concerned with interdomain routing rather
than host identification. CIDR has a strategy for the allocation and use of IPv4 addresses,
rather than a new proposal.

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A dynamic document is created by a Web server whenever a browser requests the document. When a request arrives, the Web server runs an application program that creates the dynamic document.

Common Gateway Interface (CGI) is a technology that creates and handles dynamic documents.

CGI is a set of standards that defines how a dynamic document should be written, how the input data should be supplied to the program and how the output result should be used.

CGI is not a new language, but it allows programmers to use any of several languages such as C, C++, Bourne Shell, Korn Shell or Perl.A CGI program in its simplest form is code written in one of the languages supporting the CGI.


This is what all about the CGI for the internet.
Enjoy.....

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File Transfer Protocol (FTP) is the standard mechanism provided by TCP/IP for copying a file from one host to another. The FTP protocol is defined in RFC959. It is further defined in RFC 2227, 2640, 2773 for updated documentation.

In transferring files from one system to another, two systems may have different ways to represent text and data. Two systems may have different directory structures. All of these problems have been solved by FTP in a very simple and elegant way.

FTP differs from other client–server applications in that it establishes two connections between the hosts. One connection is used for data transfer (port 20), he other for control information (port 21). The control connection port remains open during the entire FTP session and is used to send control messages and client commands between the client and server. A data connection is established using an ephemeral port.

The data connection is created each time a file is transferred between the client and server. Separation of commands and data transfer makes FTP more efficient. FTP allows the client to specify whether a file contains text (ASCII or EBCDIC character sets) or binary integers. FTP requires clients to authorise themselves by sending a log name and password to the server before requesting file transfers.

Since FTP is used only to send and receive files, it is very difficult for hackers to exploit.