Web resource: what it is

What is a web resource

Modern Society cannot be submitted without the Internet. Each time, entering certain pages or simply sitting on social networks, we do not think about special terminology and about the difference of certain things wealthy. This article will deal with what, in fact, the website and web resource, which types of web resources exist, and what are their features. If you want to independently learn how to create websites, we invite you to pass our free online programming and layout courses.

Website concepts and web resources

Web site - A set of files, documents reflected by programming language in such a way that they see them users of the Internet. In other words, sites include any text, graphical, audio or video information collected on the page or multiple pages.

Determines the uniqueness of a web site, as a rule, a domain name. BUT Web resource - This is a node or point in which a special identifier is enabled, which allows you to easily find the page on the Internet. Most often, one domain corresponds to one web resource, but sometimes it happens that several web resources are located on a single domain, or one web resource has several domains for itself.

The larger the website, the greater the probability that it will be located on several domains. The same domain, as a rule, includes several websites, as a rule, it is possible for free web hostings.

Types of Web Resources

Different types of web resources

There are certain differences in web resources by type:

  1. By availability of services:

    • Open - When everyone without exception, all services are available without exception.
    • semi-open - when you need to register, as a rule, free
    • Closed - private and personal sites created for organizations and components where you can only have a special invitation.
  2. By physical location:

    • publicly available - open to all users
    • Local - open only in the Local Network Access Area (special computer network on a sufficiently small area).
  3. According to the information presentation scheme:
    • Information resources - include thematic sites (with narrowly directed subjects) and thematic portals (usually large web resources with comprehensive information, as well as the ability to communicate within the resource).
    • Internet representations - as a rule, sites of those who own business. There are different subspecies of such sites: a visit site, promotional site, online store, etc.
    • Web services - also include various subspecies (blogging, video hosting, search services, etc.) and are designed to perform a certain number of tasks on the Internet.

You can also highlight the most interesting. Types of Web Resources Site Types : Website for advertising. On this site, the main role is usually played by the "design" as a way to improve the appearance of something or more successfully visualize (in which case we can talk about "design" as a form of activity).

Website for business. In this case, the web resource will not be too voluminous by content, because The main purpose of such sites is to consolidate as if the showcase of the most important information necessary to the potential customer or the consumer. However, it is also worth noting that there are intra-smile web resources (corporate - where the company's marketing policy is taken into account, all the questions of customers and customers are considered).

Website storage

In order for a particular site to function normally, it must be kept in a safe place. For such purposes there are special servers. Otherwise, they are called hardware servers, or web servers. There is also a special name of services that are provided to save sites. They are called web hosting.

It is noteworthy that earlier to save the site, it was necessary to have some single server. Now the Internet is developing so lightning, that often users resort to an option when several sites can be stored on one site within the framework of the so-called. Virtual hosting.

The other option is not excluded when the same site is stored at different addresses and servers. In this case, there is an original and a copy (as it is different in a different way - the mirror version of the site)

It is worth noting that for web developers such an order of things is quite acceptable and better solution. Indeed, in this case, it is not necessary to create a specific service for storing a particular site data, and to use an already well-processed server for storing all data as a whole.

It is also worth noting the important role of administrators or the so-called. Sisadminov (in the Language of slang), which play an important role in the formation of a successfully functioning web resource, following its filling and sustainable parameters.

The modern development of the Internet is one way or another forces us to be aware of those things that we face in this network itself. If you decide to start conducting your blog, open an online store, or simply "in the topic" what you have dealing with the network, it is very important to know what a web resource is.

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What is an online resource?

Internet resource (Synonyms "Web Resource, Website, Web Service, Website") - This is a combination of integrated technical and software and hardware tools, as well as information intended for publication in the World Wide Web. The Internet resource may contain information in text, graphic and multimedia form. Each Internet resource must have a unique address that allows it to find it on the network.

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The concept of "Internet resource" is more often used in a special vocabulary, since its etymology goes back to special computer terminology. A resource, or system resource, information technology is called a physical or virtual component of limited availability in a computer system.

That is, any device in the computer can be considered as a resource. Resources also use not only physical components (memory elements, etc.), but also virtual, such as files. It is to the virtual part of the resources the idea of ​​web (internet) resources is rising. In the era of the young Internet, the network was looking for documents, or rather the files that had a special address. Soon under the resource on the Internet, they also began to understand the entire information system and associated network (for example, electronic libraries, etc.).

When using terms on the Internet, the term "resource" received similar characteristics (identification and notation, addressing and technical processing). However, there was also a certain specificity that caused long discussions among specialists. The most famous plot of this discussion was a dispute about the classification of Internet resources. However, in reality, there were more reasons for disputes. In addition to technical issues, experts discussed social, linguistic and even philosophical aspects.

The further development of the Internet has led not only to an increase in the number of websites, but also to the variety of their functions and destination. Questions about the application of the term "Internet resource" remained, but in everyday life it is extremely rare.

the Internet

The Internet (English) - The worldwide system of combined computer networks for storing and transmitting information. Often referred to as the worldwide network and the global network, as well as just a network. Built on the TCP / IP protocol stack. WORLD WIDE WIDE WIDE WIDE WWW and Many other data transmission systems are based on the Internet.

Basic Internet resources

Consider the main resources of the Internet. The most popular Internet resource is the World Wide Web, or WWW, which is a huge amount (over a billion) multimedia documents, a distinctive feature of which other than an excellent appearance is the ability to refer to each other. This means the presence in the current document link implementing the transition to any WWW document, which can physically be posted on another computer network. WWW (World Wide Web, World Wide Web) - A set of interrelated hypermedia documents

The next network resource is FTP, which is a storage and transfer system of all sorts of files. FTP (File Transfer Protocol, file transfer protocol) - repository and system for sending all sorts of files.

The oldest Internet resource is E-mail (email). E-mail (email) - Email sending system.

For discussions on the network, a global distributed system called a newsgroup is intended. One of the most popular systems of this kind is a group of news Usenet.

The Telnet service allows you to connect to a remote computer and work with its resources. This is a service for remote control of computers.

Finally, there is an IRC (CHAT) system on the Internet, implementing live communication of users in real time by entering text from the keyboard.

The World Wide Web

The World Wide Web (eng. World Wide Web. ) - a distributed system that provides access to interconnected documents located on various computers connected to the Internet. To designate the World Wide Web also use the word web (eng. Web. "Web") and abbreviation Www . World Wide Web is the largest worldwide multilingual information storage in electronic form: tens of millions of related documents that are located on computers located around the globe. It is considered the most popular and interesting Internet service, which allows access to information regardless of its location. To learn the news, learn something or just to have fun, people watch TV, listen to the radio, read newspapers, magazines, books. The World Wide Web also offers its users broadcasting, video information, press, books, but with the difference that all this can be obtained without leaving home. It does not matter what information is presented in the information that interests you (text document, photography, video or sound fragment) and where this information is geographically (in Russia, Australia or on the bank of the ivory) - you will get it in a few minutes to your computer.

World wide web forms hundreds of millions of web servers. Most World Wide Web Resources are a hypertext. Hypertext documents posted in the World Wide Web are called web pages. Several web pages made by the common theme, design, as well as related links and usually located on the same web server are called the Web site. Special programs are used for downloading and viewing web pages - browsers. World Wide Web has caused a real revolution in information technology and a boom in the development of the Internet. Often, speaking of the Internet, they mean by the World Wide Web, but it is important to understand that this is not the same thing.

History of World Wide Web

The inventors of the World Wide Web are considered to be Tim Berners-Lee and, to a lesser extent, Robert Kayo. Tim Berners-Lee is the author of HTTP technologies, URI / URL and HTML. In 1980, he worked in the European Council on Nuclear Research (FR. Conseil Européen Pour La Recherche Nucléaire, CERN) software consultant. It was there, in Geneva (Switzerland), he wrote the Enquier program for his own needs (English. Enquire, you can freely translate as the "investigator"), which used random associations for storing data and laid the conceptual basis for the World Wide Web.

In 1989, working in CERN over the internal network of the organization, Tim Berners-Lee offered a global hypertext project, now known as the World Wide Web. The project implied the publication of hypertext documents related to the hyperlinks, which would facilitate the search and consolidation of information for CERN scientists. To implement the project Tim Berners-Lee (jointly with his assistants), URI identifiers were invented, HTTP protocol and HTML language. These are technologies that can already be submitted to the modern Internet. In the period from 1991 to 1993, Berners-Lee improved the technical specifications of these standards and published them. But, nevertheless, officially the year of the birth of the World Wide Web should be considered 1989.

Within the framework of the Berners-Lee project, the world's first HTTPD web server and the world's first hypertext web browser called Worldwideweb. This browser was simultaneously a WYSIWYG editor (Sokr. From the English. What You See Is What You GET - you see, then you will receive), its development was launched in October 1990, and finished in December of the same year. The program worked in the NextStep environment and began to spread over the Internet in the summer of 1991.

The world's first website was posted by Berners-Lee on August 6, 1991 on the first web server, accessible to http://info.cern.ch/. The resource determined the concept of the World Wide Web, contained instructions for installing a web server, using a browser, etc. This site was also the first online directory in the world, because later Tim Berners-Lee posted and supported a list of links to other sites.

Since 1994, the main work on the development of the World Wide Web, a consortium of the World Wide Web Consortium, W3C, based and still headed by Tim Berners-Lee. This consortium is an organization that develops and implementing technological standards for the Internet and the World Wide Web. The W3C mission: "Fully disclose the potential of the World Wide Web by creating protocols and principles guaranteeing long-term network development." Two other major consortium tasks - to provide complete "network internationalization" and make a network accessible to people with disabilities.

W3C develops uniform principles and standards for the Internet (called "Recommendations", English. W3C Recommendations), which are then embedded by manufacturers of programs and equipment. Thus, compatibility is achieved between software products and equipment of various companies, which makes the worldwide network more perfect, universal and convenient. All recommendations of the World Wide Web Consortium are open, that is, not protected by patents and can be introduced by any person without any financial deductions to the consortium.

Structure and principles of the World Wide Web

World Wide Web form millions of web servers on the Internet worldwide. The web server is a program running on a computer connected to the network and using the HTTP protocol for data transmission. In the simplest form, such a program receives an HTTP request over a specific resource network, finds the appropriate file on the local hard disk and sends it to the network requested to the computer. More complex web servers are capable of responding to HTTP request to dynamically generate documents using templates and scripts.

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To view information received from the web server, a special program is applied on the client computer - a web browser. The main function of the web browser is the display of a hypertext. The World Wide Web is inextricably linked with the concepts of hypertext and hyperlinks. Most of the information in the web is a hypertext.

To facilitate the creation, storage and display of hypertext, the World Wide Web traditionally uses the HTML language (HyperText Markup Language, "Hypertext Marking Language"). Work on the creation of (markup) of hypertext documents is called a clash, it is made by a webmaster or a separate specialist in the markup - the vertellor. After HTML markup, the resulting document is stored in a file, and such HTML files are the main type of worldwide web resources. After the HTML file becomes available to the web server, it starts to call "a web page". Set of web pages forms a website.

Hypertext web pages contains hyperlinks. Hyperlinks help worldwide web users easily move between resources (files), regardless of whether resources are on a local computer or on a remote server. To determine the location of resources in the World Wide Web, uniform resource locators URL (English Uniform Resource Locator) are used. For example, the full URL of the main page of the Russian section Wikipedia looks like this: http://ru.wikipedia.org/wiki/Spalvnaya_Strica . Such URLs combine the identification technology of the URI (eng. Uniform Resource Identifier - "Uniform resource identifier") and DNS domain name system (eng. Domain Name System). The domain name (in this case is ru.wikipedia.org) as part of the URL indicates a computer (more precisely, one of its network interfaces), which executes the code of the desired web server. The URL of the current page usually can be seen in the address bar of the browser, although many modern browsers prefer the default to show only the domain name of the current site.

World Wide Web Technologies

To improve the visual perception of the Web, CSS technology has become widely applied, which allows you to set single design styles for a variety of web pages. Another innovation that is worth paying attention is the URN resource designation system (Eng. Uniform Resource Name).

The popular development concept of the World Wide Web is the creation of a semantic cobweb. The semantic web is a superstructure over the existing worldwide web, which is designed to make information posted on the network more understandable for computers. The semantic web is the concept of a network in which each resource in the human language would be equipped with a description, understandable to the computer. Semantic web opens access to well-structured information for any applications, regardless of the platform and regardless of programming languages. The programs will be able to find the necessary resources themselves, process information, classify data, identify logical connections, draw conclusions and even make decisions based on these conclusions. With widespread and competent implementation, the semantic web can cause a revolution on the Internet. To create a resource description computer, a RDF format is used in the semantic web (eng. Resource Description Framework), which is based on XML syntax and uses URI identifiers to designate resources. New in this area is RDFS (English RDF Schema) and SparQL (English Protocol and RDF Query Language) (pronounced as "Sparkle"), a new query language for quick access to RDF data.

Main applied worldwide cobwebs

HTML (Hyper Text Markup Language, Hypertext Marking Language). This is the format of hypermedia documents used in WWW to present information. This format describes the content of the document, its structure, as well as its connection with other documents. The appearance of the document on the user's screen is determined by the navigator: if the user works with a graphic or text terminal, in any case the document on the screen will have a different look. HTML performs an integrating role for the elements of the hypermedia document. File names in the .html format, usually end with .html (or have an extension .htm in case the server works under Windows). URL (Uniform Resource Locator, universal pointer to the resource). Such a name is verbal references to any Internet information resources. Internet resources are available across the IP address of a specific computer. HTTP (Hypertext Transfer Protocol, Hypertext Transmission Protocol). Such a name is a protocol in which the client and WWW server interact to transmit the hypermedia document to the client. Www - Direct access service that requires a full-fledged Internet connection. It requires fast communication lines for documents containing a lot of graphic or other non-text information. When speeds are lower, part of the advantages that www has been so popular.

Principle of operation

Like most other Internet services, the World Wide Web works within the client-server model. As a server, as a rule, a computer connected to the network is on which a special program works. It is this program most often called a web server. The client is any computer currently connected to the Internet on which the web publishing program is running - browser (browser) (from the English. Browse - flip, scroll). The browser work is to exchange information with a web server, obtaining the necessary documents to the user, processing the obtained hypertext information and the display of the document on the screen. The exchange of information between the web server and the browser is carried out using the HTTP protocol.

Work with browser

Today, ten years after the invention of the HTTP protocol, the World Wide Web, the browser is the most complex software that combines ease to use and the wealth of opportunities. Browser not only opens up the user the world of hypertext resources of the World Wide Web. It can also work with other network services, such as FTP, Gopher, Wais. Together with the browser, a program is usually installed for using email services (e-mail) and news (NEWS). In fact, the browser is the main program to access the network services. Through it, you can access virtually any Internet service, even if the browser does not support work with this service. This uses specially programmed web servers that associate a worldwide web with this network service. An example of this kind of web servers is numerous free email servers with a web interface (see http://www.mail.ru) Today there are many browser programs created by various companies. Browsers such as Netscape Navigator and Internet Explorer received the greatest distribution and recognition. It is these browsers that make up the main competition among themselves, although it is worth noting that these programs are largely similar. This is understandable, because they work on the same standards - Internet network standards. Work with the browser begins with the fact that the user is gaining the URL of the resource in the address bar to which he wants to access, and presses the Enter key.

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The browser sends a request to the specified network server. As the elements of the web page specified by the user comes from the server, it gradually appears in the working window of the browser. The process of obtaining elements of the page from the server is displayed in the lower "status" string of the browser.

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The text hyperlinks contained in the received web page are usually highlighted by color different from the color of the remaining text of the document, and are emphasized. References indicating the resources that the user has not yet been viewed, and links to already visited resources usually have different color. Images can also function as hyperlinks. Regardless of whether the text link or graphic, if you bring the mouse cursor on it, its form will change. Simultaneously in the status bar of the browser will appear the address to which the link indicates.

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When you click on the hyperlink, the browser opens the resource in the working window to which it indicates, with the previous resource from it is unloaded. The browser leads a list of browsing pages and the user if necessary, can go back on the page viewed chain. To do this, you need to click on the "Back" button ("Back") in the browser menu - and it will return to the page you viewed before you opened the current document. Each time you press this button, the browser will return For one document back in the list of visited documents. If suddenly you have come back too far, use the "Forward" button ("Forward") the browser menu. It will help you move forward on the list of documents. Stop "Stop" ("Stop") will stop the documentation of the document. The "Refresh" button allows you to restart the current document from the server. The browser in its window can show only one document: to display another document it unloads the previous one. It is much more convenient to work simultaneously in several browser windows. Opening a new window is carried out using the menu: File - Create - window (or CTRL + N key combination).

Work with document

The browser allows a set of standard operations on the document. You can print the web page loaded into it (in Internet Explorer it is done using the "Print" button or from the menu: File - print ...), save to disk (Menu: File - Save how ...). You can find the text fragment you are interested in in the downloaded page. To do this, use the menu: Edit - Find on this page .... And if you are interested in how this document looks like in the original hypertext, which processed the browser, select in the menu: View - in the form of HTML. When the user is on the Internet, the user finds a particular page for it, it uses the ability to set bookmarks provided in browsers. By analogy with bookmarks noted by interesting places of the book). This is done through the menu: Favorites - add to favorites. After that, the new tab appears in the list of bookmarks, which can be viewed by clicking the "Favorites" button on the browser panel or via the Favorites menu. You can delete bookmarks, modify, organize in folders using the menu: Favorites - Original Favorites.

Work through proxy server

After downloading the web page, the browser is placed on time and all its elements (pictures, animations, sound files) in a special buffer in the computer's memory. Due to this, it is loaded very quickly during re-access. With regard to a separate computer, the location in the RAM and on the rigid disk of the computer, which is used to store the viewed web pages, is called "cache" (eng. Cache). Within the framework of the local network of the organization, a common buffer can be organized in which web pages are visible to all computers on the local network. It is called a "proxy server" (eng. Proxy-server). If you request a browser to receive a document from the network, the proxy server checks whether it is already in its cache of the requested information. If there is something available, the proxy server is reconciling the time of creating the original document and its cache. If they are identical, then the proxy server simply refers a copy from the cache browser. Such a work order significantly reduces the size of the traffic, saves network resources. In addition, when using a proxy server, the time of waiting for the requested information is reduced - the most frequently requested pages are loaded to the amount faster. Modern proxies are additionally exchanged with each other information about the documents stored in them, due to this, the efficiency of their use significantly increases. To configure your browser to work with a proxy server, you need to call the settings window through the menu: Service - Observer Properties ..., and Select the Connection tab. Press the Network Setup button ... And put the box to use the proxy server. In the input field below, you must enter the name of the proxy server and the port through which information will be exchanged with it (this data user receives from its Internet provider).

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Netscape Navigator and Microsoft Internet Explorer also provides a mechanism for embedding additional features independent manufacturers. Modules that expand the browser capabilities are called plugins (plug-in). Baizers work on computers running various operating systems. This gives the basis for talking about the independence of the World Wide Web on the type of computer used by the user and the operating system.

Search for information on the Internet

Recently, a new powerful mass media is seen in the World Wide Web, the audience of which is the most active and educated part of the world's population. Such a vision corresponds to the real state of affairs. In the days of significant events and shocks, the load on network nodes of news increases dramatically; In response, resources devoted to reader demand instantly appear on the incident. Thus, during the August 1998 crisis on the CNN television and radio company (http://www.cnn.com), the news appeared much earlier than Russian media reported. At the same time, the RIA RosBusinessConsulting server was widely fame (http://www.rbc.ru), providing fresh information from financial markets and the latest news. Many Americans watched the progress of voting on the impeachment to the US President Bill Clinton on the net, and not at TV screens. The development of the war in Yugoslavia was also instantly reflected in a variety of publications, reflecting a variety of points of view on this conflict. Many people familiar with the Internet more interlace, believe that you can find any information on the network. This is really so in the sense that there you can come across the most unexpected resources in the form and content. Indeed, the modern network is able to offer its user a lot of information of the most different profile. Here you can get acquainted with the news, it is interesting to spend time, gain access to a variety of reference, encyclopedic and educational information. It is only necessary to emphasize that although the overall information value of the Internet is very large, the information space itself is inhomogeneously qualitatively, since resources are often created on an ambulance hand. If, when preparing a paper publishing, its text is usually read by several reviewers and adjustments are made to it, then in the network this stage of the publishing process is usually absent. So, in general, to the information that has learned from the Internet should be treated with a slightly greater caution than the information found in the print publication. However, the abundance of information has a negative side: with an increase in the number of information, it becomes more and more difficult to find such information, which is currently needed. Therefore, the main problem that occurs when working with the network is to quickly find the necessary information and understand it, evaluate the informational value of a resource for its purposes.

To solve the problem of finding the necessary information on the Internet there is a separate type of network service. We are talking about search servers, or search engines. The search servers are quite numerous and diverse. It is customary to distinguish search indexes and directories. Index servers They work as follows: regularly read the content of most network web pages ("index" them), and put them in whole or in part in the common database. Separator users have the ability to search for this database, using keywords related to the topic of interest. The issuance of search results usually consists of excerpts of the recommended toe of the user's user and their addresses (URL) decorated in the form of hyperlinks. Working with search servers of this type is convenient if there is a clear idea of ​​the search. и

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Problems and prospects for the development of the World Wide Web

Almost any information that is served for public access can be reflected by WWW. If something cannot be displayed in WWW, this is due only to some restrictions and disadvantages of WWW. First, the connection between the client and the server is disposable: the client sends a request, the server gives the document, and the connection is interrupted. This means that the server does not have a client notification mechanism about changing or entering new data. This problem is today being solved in several ways: a new version of HTTP protocol is being developed, which will maintain a long connection, data transmission into several threads, distribution of data transmission channels and control them. If it is implemented and will be supported by standard WWW software, it will remove the aforementioned flaws. Another way is to use navigators that can locally execute programs in interpretable languages, such as the Sun Microsystems Java project. Another solution to this problem is to use AJAX technology, based on XML and JavaScript. This allows you to access the data from the server when the WWW page is already loaded from the server.

Currently there are two trends in the development of the World Wide Web: Semantic Web and Social Web.

  • Semantic web It involves improving the connectedness and relevance of information in the World Wide Web through the introduction of new metadata formats.
  • Social web Remies to work on the streamlining of the information available in the web, performed by the users themselves. As part of the second direction of developments, which are part of the semantic web, are actively used as tools (RSS and other web channel formats, OPML, XHTML microformats). Partially semantized sections of the Wikipedia categories helps users consciously move in information space, but very soft requirements for subcategories do not give reason to hope for expanding such sites. In this regard, interest may be attempts to draw up atlases of knowledge.

There is also a popular Web 2.0 concept, which generalizes several directions of development of the World Wide Web.

Web 2.0

The development of the WWW recently is significantly carried out by the active introduction of new principles and technologies that have received the general name of Web 2.0 (web 2.0). The term of web 2.0 first appeared in 2004 and is intended to illustrate high-quality changes in WWW on the second decade of its existence. Web 2.0 is a logical improvement of the web. The main feature of Web 2.0 is to improve and accelerate the interaction of websites with users, which led to a rapid growth of user activity. This manifested itself in:

Web 2.0 introduced an active data exchange, in particular:

  • export of news between sites;
  • Active information aggregation from sites.
  • Using the API to separate the site data from the site itself

From the point of view of the implementation of Web 2.0 sites, it improves the requirements for simplicity and convenience of sites for ordinary users and aims to rapidly drop the qualifications of users in the near future. The list of standards and approvals (W3C) is compliance with the forefront. This is in particular:

  • standards of visual design and functionality of sites;
  • Typical Requirements (SEO) of search engines;
  • XML standards and open information exchange.

On the other hand, on web 2.0 decreased:

  • Requirements for "brightness" and "creativity" of design and filling;
  • need for integrated websites (portals);
  • The value of offline advertising;
  • Business interest in major projects.

Thus, Web 2.0 recorded the transition of WWW from single expensive complex solutions in highly typed, cheap, easy to use sites with the possibility of effective information sharing. The main reasons for such a transition were:

  • Critical lack of quality information filling;
  • The need for active user expression in www;
  • Development of search technology and information aggregation in WWW.

The transition to a web 2.0 technology complex has such consequences for the global information space WWW as:

  • The success of the project is determined by the level of active communication of the project users and the quality level of information filling;
  • Sites can achieve high performance and profitability without large capital investments due to successful positioning in WWW;
  • Separate WWW users can achieve significant success in implementing their business and creative plans in WWW without their own sites;
  • The concept of a personal site is inferior to the concept of "blog", "Author's heading";
  • The fundamentally new roles of the active user WWW appear (forum moderator, authoritative members of the forum, blogger).

Examples of web 2.0 We give a few examples of sites illustrating web 2.0 technologies and which actually changed WWW environment. This is in particular:

  • Livejournal.com. - the global community of bloggers;
  • ebay.com. - Internet auction with self-regulating community;
  • Wikipedia.org. - the world's largest encyclopedia;
  • ODP (Dmoz.org) - The largest directory of sites, which are edited by man.
  • Facebook.com. - Global social network;
  • Gmail.com. - one of the most popular email services;
  • Reddit.com. - social network of news;

In addition to these projects, there are other projects that form a modern global environment and based on the activity of their users. Sites, filling and popularity of which are formed, first of all, not by the effort and resources of their owners, and the community of users interested in the development of the site make up a new class of services that define the rules of the global WWW environment.

FTP.

FTP.

FTP. (eng. File Transfer Protocol - File Transfer Protocol) - Standard Protocol designed to transfer files by TCP networks (for example, Internet). FTP is often used to download network pages and other documents from a private development device to open hosting servers.

The protocol is built on the client-server architecture and uses different network connections for transmitting commands and data between the client and the server. FTP users can pass on authentication by passing the login and password with the open text, or if it is permitted on the server, they can connect anonymously (such an access method is often considered as safer, as it does not expose user passwords threat interception). You can use the SSH protocol for safe transmission hiding (encrypting) login and password, as well as encrypting content.

The first client FTP applications were interactive command-line tools that implement standard commands and syntax. Graphic user interfaces have since been developed for many operating systems used to this day. Among these interfaces as a common web design program like Microsoft Expression Web and specialized FTP clients (for example, Cuteftp).

FTP is one of the oldest application protocols that appeared long before HTTP, and even to TCP / IP, in 1971. It is also widely used to distribute software and access to remote hosts.

FTP differs from other applications in that it uses two TCP connections to transfer the file:

  • Managing connection - connection to send commands to the server and receiving answers from it. Telnet protocol is used for the control channel.
  • Data connection - connection to transfer files.

History

The first implementation of the Protocol (1971) provided for the exchange between the client and the server messages consisting of the header (72 bits) and the data variable data. The message header included the request to the FTP server or the answer from it, the type and length of the transmitted data. The data parameters were transmitted as data (for example, path and file name), information from the server (for example, a list of files in the directory) and the files themselves. Thus, commands and data were transmitted to the same channel.

In 1972, the protocol was completely changed, and made a view close to modern. Commands with parameters from the client and server responses are transmitted by Telnet connection (control channel), a separate connection (data channel) is created for data transmission.

In the following editions, the ability to work in passive mode was added, the file transfer between FTP servers was added, commands for obtaining information, changing the current directory, creating and deleting directories, saving files under a unique name. Some time there were commands for sending emails through FTP, but subsequently they were excluded from the protocol.

In 1980, the FTP protocol began to use TCP. The last edition of the protocol was released in 1985. In 1997, an addition to the protocol appeared, allowing to encrypt and sign information in the control channel and the data channel. In 1999, an add-on dedicated to the internationalization of the protocol, which recommends using UTF-8 encoding for server commands and responses and defines the new Lang command that sets the response language.

Protocol description

Difference from http

Property FTP. Http.
Based on work sessions Yes No
Built-in user authentication Yes No
Mainly provided for transfer Large binary files Small text files
Connection model Double connection Single connection
Mainly adapted for reception / transfer Reception and transmission Takery
Supports text and binary transmission modes Yes No
Supports Specifying Types of Transmitted Data (MIME Headers) No Yes
Supports operations on the file system (MKDIR, RM, RENAME, etc.) Yes No

A rather bright feature of the FTP protocol is that it uses the multiple (at least dual) connection. In this case, one channel is the manager through which the server commands receive and its answers are returned (usually through TCP port 21), and through the rest there is a data transfer, one channel for each transmission. Therefore, within the framework of the FTP session, you can simultaneously transmit several files at the same time, and in both directions. For each data channel, its TCP port is opened, the number of which is selected either by the server or by the client, depending on the transmission mode. The FTP protocol has a binary transmission mode, which reduces the overhead of traffic and reduces data exchange time when transmitting large files. The protocol of HTTP necessarily requires coding of binary information into a text form, for example, using the BASE64 algorithm. Scheduled through the FTP protocol, the client is included in the session, and all operations are carried out within this session (in other words, the server remembers the current state). HTTP protocol does not remember anything. Its task is to give data and forget, so the status memorization when using HTTP is carried out by external with respect to the protocol methods. FTP operates at the OSI application level and is used to transfer files using TCP / IP. To do this, a FTP server, waiting for incoming queries, should be launched. Computer client can contact the server by port 21. This compound (control flow) remains open during the session. The second connection (data flow) can be opened as a server from port 20 to the port of the corresponding client ( Active mode ), or by the client from any port to the port of the corresponding server ( Passive mode ) What is necessary to transfer the data file. The control stream is used to work with the session - for example, the exchange between the client and the server commands and passwords using a Telnet-like protocol. For example, "RETR file name" will send the specified file from the server to the client. Due to this two-port structure, FTP is considered an external-eye protocol, unlike in-band HTTP.

Data connection and transmission

The protocol is defined in RFC 959. The server responds over the flow of three-digit ASCII status ASCII codes with an optional text message. For example, "200" (or "200 OK") means that the last team has been successfully completed. The numbers represent the response code, and the text is clarification or request. The current data stream transmission can be interrupted using an interrupt message sent over the control stream. FTP can work in active or Passive mode From whose choice is the method of installing the connection. In older versions, only the 20th port (active mode) was used to transmit data, in modern versions of the FTP servers, the port for the data channel can be assigned by a non-standard port server (N> 1024) ports (passive mode). In active mode, the client creates a control TCP - Connection with the server and sends its IP address and arbitrary client port number, after which it is waiting until the server starts the TCP connection with this address and port number. In the event that the client is behind the firewall and cannot accept an incoming TCP connection, passive mode can be used. In this mode, the client uses the control stream to send the PASV command server, and then receives its IP address and port number from the server, which is then used by the client to open the data flow from an arbitrary client port to the address and port.

The difference in the work of the passive mode and active. Server and Client Actions in Active and Passive Mode

Active mode Passive mode
1. The client establishes communication and sends a request to 21 server port from port N (n> 1024) 1. The client establishes a connection and sends a request (reports that it is necessary to work in passive mode) on the 21 server port from the port N (n> 1024)
2. The server sends an answer to the client port n (n> 1024) 2. The server sends the answer and tells the port number for the data channel P (p> 1024) to the port n (n> 1024) of the client
3. The server establishes communication to transfer data by port 20 to the port of the client n + 1 3. The client establishes communication to transmit data by port N + 1 to the port port port P (P> 1024)

Active FTP. Profitable for the FTP server, but harmful to the client side. FTP server is trying to connect with random high (by number) ports on the client, such a connection will certainly be blocked by a firewall on the client side. Passive FTP. Profitable for the client, but harmful to the FTP server. The client will make both connections to the server, but one of them will be at a random high port, such a connection will certainly be blocked by a firewall on the server side.

Both modes were updated in September 1998 to support IPv6. At this time, further changes in the passive regime were carried out, updating it to an extended passive regime.

During network data transfer, four data views can be used. :

  • ASCII - Used for text. Data, if necessary, before the transmission is converted from a symbolic view on a host-sender in an "octalite ASCII", and (again, if necessary) into the character representation of the host. As a result, this mode is not suitable for files containing not only the usual text.
  • Image mode (usually referred to as binary) - the sender device sends each byte file per byte, and the recipient saves the byte flow upon receipt. Support for this mode was recommended for all FTP implementations.
  • EBCDIC - Used to transfer ordinary text between hosts in EBCDIC encoding. Otherwise, this mode is similar to the ASCII mode.
  • Local mode - allows two computers with identical installations to send data in its own format without conversion in ASCII.

For text files, various control formats and configuration of the recording structure are provided. These features were designed to work with files containing Telnet or ASA formatting.

Data transfer can be carried out in any of the three modes. :

  • Potion mode - The data is sent as a continuous stream, freeing the FTP from the execution of any kind of processing. Instead, all processing is performed by TCP. The end indicator is not needed, except for dividing data on the record.
  • Block mode - FTP breaks data into several blocks (header unit, number of bytes, data field) and then transmits them TCP.
  • Compressive mode - The data is compressed by a single algorithm (usually, encoding the lengths of the series).

Authentication

FTP authentication uses the usual username / password diagram to provide access. The username is sent to the User command server, and the password is the Pass command. If the information provided by the client is accepted by the server, the server will send an invitation to the client and the session begins. Users can if the server supports this feature, log in to the system without providing credentials, but the server can provide only limited access for such sessions.

Anonymous FTP.

Host, providing an FTP service, can provide anonymous access to FTP. Users usually log in as "anonymous" (may be case-dependent on some FTP servers) as a username. Although usually users are asked to send their email address instead of password, no verification is actually done. Many FTP hosts that provide software updates support anonymous access.

Nat-Pt.

Especially for the operation of the FTP protocol through the firewalls, the NAT extension was made, called NAT-PT (RFC2766), which allows you to translate incoming connections from the server to the client through NAT. In the process of such a connection, NAT replaces the transmitted data from the client, specifying the server to the server and the port with which the server will be able to connect, and then broadcasts the connection from the server from this address to the client to its address. Despite all measures and innovations adopted to support the FTP protocol, in practice, the NAT-PT function is usually disconnected in all routers and routers in order to provide additional safety from viral threats.

NAT and Flashing Firewall

FTP usually transmits data if the server is connected to the client, after the client sent the port command. This creates a problem for both NAT and firewalls that do not allow connections from the Internet to internal hosts. For NAT, an additional problem is that the representation of IP addresses and the port number in the Port command refers to the IP address and port of the internal host, instead of a public IP address and NAT port. There are two approaches to this problem. The first is that the FTP client and the FTP server use the PASV command, which causes a data connection set from the client to the server. The second approach is a change for the NAT of the PORT command values ​​using a gateway at the applied level.

Web browsers support

Most of the usual web browsers can retrieve files located on FTP servers, although they may not support protocol extensions like FTPS. When the FTP address is specified, and not the HTTP address, the available content on the remote server seems similar to the other web content. Fully functional FTP client can be launched in Firefox as FireFTP /

Syntax

The FTP URL syntax is described in RFC1738, in form: FTP: // [<<user> [: <Password>] @] <host> [: <port>] / <path> (parameters in square brackets are optional). For example: FTP: //Public.ftp-servers.example.com/Mydirectory/MyFile.txt

or: ftp: // user001: [email protected]/mydirectory/myFile.txt

More detailed about specifying the username and password is written in the browser documentation. By default, most web browsers use passive (PASV) mode that is better by the end user firewalls.

Security

FTP was not developed as protected (especially according to the current standards) protocol and has numerous vulnerabilities in defense. In May 1999, the authors of RFC 2577 brought vulnerabilities to the next list of problems:

  • Hidden Attacks (Bounce Attacks)
  • SPOOF ATTACKS)
  • Broast Force Attacks (Brute Force Attacks)
  • Package interception, Sniffing (Packet Capture, Sniffing)
  • User name protection
  • Capture ports (Port Stealing)

FTP cannot encrypt its traffic, all transmissions - open text, so user names, passwords, commands and data can be read by anyone, able to intercept the packet over the network. This problem is characteristic of many Internet protocol specifications (including SMTP, Telnet, POP, IMAP) developed before creating such encryption mechanisms such as TLS and SSL. The usual solution to this problem is to use "Safe", TLS-protected versions of vulnerable protocols (FTPs for FTP, Telnets for Telnet, etc.) or another, more protected protocol, like SFTP / SCP provided with most implementing Secure Shell Protocol .

Safe FTP.

There are several methods of secure file transfer, in one or another time called "Safe FTP".

Ftps.

Explicit FTPs - Expansion of the FTP Standard, allowing clients to require that the FTP session is encrypted. This is implemented by sending the "AUTH TLS" command. The server has the ability to allow or reject connections that do not request TLS. This protocol extension is defined in Specifications 4217. An implicit FTPS is an outdated standard for FTP, which requires the use of SSL or TLS connections. This standard was supposed to use other ports other than the usual FTP.

SFTP.

SFTP, or "SSH File Transfer Protocol", is not associated with FTP, except that it also transmits files and has a similar set of commands for users. SFTP, or Safe FTP, is a program that uses SSH (Secure Shell) to transfer files. Unlike standard FTP, it encrypts both commands, and data, preventing passwords and confidential information from open transmission via the network. According to the functionality of SFTP, it looks like an FTP, but since it uses another protocol, the standard FTP clients cannot contact the SFTP server and vice versa.

FTP via SSH (not SFTP)

FTP via SSH (not SFTP) refers to the practice of tunneling the usual FTP session via an SSH connection. Since FTP uses several TCP connections, the tunneling via SSH is particularly difficult. When a lot of SSH clients are trying to install a tunnel for the control channel (the initial "client-server" connection by port 21), only this channel will be protected; When data transfer, the FTP software at any end will set new TCP connections (data channels), which will cost an SSH connection and thus lose the holistic protection.

Otherwise, for client SSH software, you need to have certain FTP knowledge to track and overwrite the FTP control flow messages and the autonomous opening of new redirects for FTP data stream.

FTP via SSH is sometimes referred to as safe FTP; But it is not worth confusing it with other methods, such as SSL / TLS (FTPS). Other methods of file transfer using SSH and not related to FTP - SFTP and SCP; Each of them and accounting and file data are always protected by the SSH protocol.

FTP. Basic concepts

FTP.

FTP. - From the English "File Transfer Protocol", translates as a "File Transfer Protocol". Using this protocol, you can connect to FTP servers and make different steps with files stored on them and folders: download from the server to your PC, download to the server, create, edit, rename, delete, assign access rights. Working with files on the FTP server is largely reminiscent of the usual actions with them on your computer.

Examples of using FTP. :

  • Loading web pages on hosting server
  • Downloading music, movies and programs with publicly available FTP servers, etc.

As practical work, go to http://www.freedrweb.com/cureit/ and hover the mouse over the link DR.Web Cureit! at the bottom of the page. In the status bar you will see the link address: ftp://ftp.drweb.com/pub/drweb/cureit/launch.exe. Here is a publicly accessible FTP server on which the Cureit utility is stored!

FTP protocol

FTP protocol File Transfer Protocol) is one of the three main Internet protocols (Mail, WWW, FTP). FTP or "File Transfer Protocol" - one of the oldest protocols on the Internet and enters its standards. Data exchange in FTP passes through the TCP channel. Built exchange using client-server technology.

Protocol - This is a consistent format for transmitting data between two devices.

FTP server.

FTP server. - This is the usual computer on which special software has been installed, allowing users to connect to it and work with files stored on it and folders just do it on their own PCs. You can connect to the FTP server freely or on unique login and password.

When working with FTP, two concepts are widely used: download and pumping. Download (In English "Download") means the process of saving folders and files from the FTP server to your computer. Downloading (In English "Upload") is the transfer of folders and files from your computer to the FTP server.

Usually, each folder (less often file) on the FTP server assign access rights: read, recording and execution. Reading means you can view a file or folder content. The record allows you to change this content. And execution makes it possible to run executable files and scripts on the server. You may encounter access rights management, for example, when developing a website when visitors need to prohibit access to some site directories and allow scripts from other directories.

FTP client

To connect to the FTP server, a special program is needed, called FTP client or FTP manager. FTP clients, both built-in somewhere and specialized, there is a great set.

FTP client - A program that allows you to connect to a remote FTP server and receive / transmit files via the FTP protocol.

General scheme of working with FTP client

First, you must specify a specific server address (URL). For example, ftp://ftp.msu.ru. Then you need to go through the registration procedure on the server. If the server is anonymous and you work with the browser program, registration will be automatically. When working with a graphic FTP client, you also can prescribe the necessary access parameters in advance, namely, the username and password. After a successful connection, you can view the contents of all server folders, which, depending on the type of FTP client, look like in a standard program to view the file system. Finding the desired file, you can copy it to the disk of the local computer, pre-specifying the destination. Copying files from a local computer to a remote FTP server is usually allowed for registered users only.

Using FTP in the educational process :

  • copying software to provide a learning process;
  • Organization of file sharing with telecommunication project partners.

FTP protocol

FTP protocol

FTP. File Transfer Protocol) is one of the three main Internet protocols (Mail, WWW, FTP). FTP or "File Transfer Protocol" - one of the oldest protocols on the Internet and enters its standards. Data exchange in FTP passes through the TCP channel. Built exchange using client-server technology.

Protocol - This is a consistent format for transmitting data between two devices. The protocol determines the following:

  • how an error will be checked;
  • Data packing method (if the package is used);
  • how the sending device reports that it has completed the message;
  • How the receiving device reports that it received a message.

There are a number of standard (reference) protocols from which you can choose the appropriate. Each protocol has its advantages and disadvantages (inconvenience); For example, some are simpler than others, some are more reliable, and some faster.

From the user's point of view, the only thing that interests it in the protocol is that the computer or device must support it (protocol) correctly if you want to contact other computers. The protocol can be implemented or in hardware or software.

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FTP is a set of rules that indicate how computers can share files on the Internet.

The FTP protocol is built in such a way that various computers with various software and various "hardware" can effectively exchange any files.

Today, many users with the word FTP associate it with Warez, MP3, JPEG and MPEG formats. But in fact, this protocol is used to transmit any types of files, from ordinary text documents to protected software files. FTP protocol is widely used in automatic payment systems over the Internet and to transfer information from satellites in space.

Forwarding and downloading files on the Internet - so important routine tasks that the FTP protocol has become widely applied before the email appears. However, with this protocol, it is much easier to access the files of another computer, rather than provide others the ability to access your files and read them.

Technical Connection Processes using the FTP Protocol

In FTP, the connection is initiated by the user protocol interpreter. Exchange management is carried out via the control channel in the Telnet protocol standard. FTP commands are generated by the user protocol interpreter and are transmitted to the server. Server Answers are sent to the user also through the control channel. In general, the user has the ability to establish contact with the server protocol interpreter and different from the user interpreter.

FTP commands define the data transmission channel parameters and the transfer process itself. They also determine the nature of working with remote and local file systems.

FTP differs from other applications in that it uses two TCP connections to transfer the file.

  • Managing connection Installed as a normal client-server connection. The server carries out a passive opening on a pre-known FTP port (21) and expects a request to connect from the client. The client performs an active opening on TCP port 21 to set a control compound. The control connection exists all the time while the client communicates with the server. This connection is used to transfer commands from the client to the server and to transfer responses from the server. The IP type of service for the control connection is set to obtain a "minimum delay", as the commands are usually entered by the user.
  • Data connection opens every time the file is transmitted between the client and the server. It also opens to other moments as we will see later. The IP service type for the data connection must be "maximum bandwidth", as this connection is used to transfer files.

The management session initializes the data transmission channel. When organizing a data transmission channel, the sequence of actions is another other than the organization of the control channel. In this case, the server initiates data exchange in accordance with the parameters agreed upon in the control session.

The data channel is installed for the same host as the control channel through which the data channel is configured. Data channel can be used both for receiving and data transfer.

A situation is possible when data can be transmitted to a third car. In this case, the user organizes the control channel with two servers and organizes a direct channel channel between them. Control commands go through the user, and data directly between servers.

The control channel must be opened when transferring data between the machines. If it is closed, the data transmission stops.

FTP address looks like this:

FTP: // User: [email protected]: 21 /

  • User - username.
  • The colon is a delimiter for the program between the username and password
  • Password - password.
  • @ - means separation between user data and address.

Next is the address directly. It can be an IP, or the address may have an alphabet value (ftp.ur.ru). After the address, the separation colon goes again, which shares the address, and the port number to which should be connected. By default, this port is 21, but there may be any digit marked by the server administrator.

The address may look like this:

FTP: / 127.0.0.1

This will mean that the name of the user Anonymous, password is e-mail address, and port 21st.

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FTP modes

When working on the FTP protocol between the client and the server, two compounds are installed - Manager (teams go on it) and Data transfer connection (files are transmitted). Control compound is equally for Active и Passive regime . The client initiates the TCP connection from the dynamic port (1024-65535) to the port number 21 on the FTP server and says "Hi! I want to connect to you. Here's my name and my password." Further actions depend on what FTP mode (active or passive) is selected.

  • В active mode When the client says "Hi!" It also tells the port number server (from the dynamic range of 1024-65535) so that the server can connect to the client to set the connection for data transmission. The FTP server connects to the specified client port number using the TCP port number 20 for data transfer. For the client, such a connection is incoming, so often work in the active mode of customers behind firewall or NAT is difficult or requires additional settings.
  • В Passive mode After the client said "Hi!", the server reports the client the TCP port number (from the dynamic range of 1024-65535) to which you can connect to set the data transfer connection. At the same time, it is easy to notice, ports in such a connection both from the client and the server side are arbitrary. In passive mode, the client can easily work with the server through its firewall, but often to support the passive mode server, the corresponding firewall configuration is already on the server side.

The main difference between the active FTP mode and the passive FTP mode is the Party that opens the connection to transfer data. In active mode, the client must be able to take this connection from the FTP server. In passive mode, the client always initiates this connection itself, and the server must be taken.

FTP is a service based exclusively on TCP (transmission management protocol). FTP is unusual in that it uses two ports, the "data" port and the "commands" port (also known as the control port). Traditionally, this is port 21 for commands and port 20 for data. However, depending on the mode, the data port will not always be 20.

In active mode, the FTP client is connected to an arbitrary unprivileged port (N> 1024) to the FTP server command port 21. Then, the client starts listening to the port n + 1 and send the FTP command port n + 1 to the FTP server. In response, the server connects to the specified client data port from its local data port 20.

In passive FTP mode, the client initiates both connections to the server, solving a problem with firewalls that filter the incoming port of the client data port. When you open the FTP connection, the client locals open two unprivileged ports (N> 1024 and N + 1). The first port contacts the server to port 21, but instead of sending the PORT command and allow the server to connect to its data port in response, the client displays the PASV command. As a result, the server opens an arbitrary unprivileged port (P> 1024) and sends the client to the port P PR command. Then, for data transmission, the client initiates the connection from the port n + 1 to port P on the server.

FTP server.

FTP server.

FTP server. - A computer that contains publicly available files and is configured to support the FTP protocol (the FTP server must have a software that supports the FTP protocol).

Currently, there are three varieties of FTP servers in the Internet:

  1. Internet-Style (access to all server files)
  2. ListServer (Limited Access)
  3. FTPmail (access via email).

Servers FTPmail The most interesting for those users who have access to the Internet are very limited, that is, they can only use email. You enter several special commands in your letter to execute your selected FTPmail server. If everything is entered correctly and your letter has come to the destination, the FTPmail server will start to search for the desired file in almost all intertwine Internet. If the file is found, then you will be transferred it, otherwise you will come a letter with information that this file in nature does not exist. The thing, of course, is good, but if you have full access to Internet resources, she you can do anything.

In the network for storing large data volumes exist FTP Server . The FTP server is a kind of file library. To pump files between FTP servers and a user's computer, the FTP protocol is used ( File Transfer Protocol - File transfer protocol).

What is the FTP server for? You can pump up your computer filed files on numerous FTP servers. There are thousands of FTP servers that provide free anonymous access to gigabytes of the most diverse information: text documents, program distribution, photographs and music files. By the FTP protocol, you can download your home pages on free servers that provide space. It is much more convenient than apply HTTP when you specify the files that need to be downloaded on a special page of the server.

When using FTP, some features of this service should be remembered, directly arising from the operating system where it originated - UNIX. Any FTP server always requires user authorization, that is, entering its name and password. Depending on this, the user will only be provided with access to certain directories and files together with the ability to carry out only permitted actions on the contents of the FTP storage.

What to do if you are not a registered user? Almost every FTP server provides the so-called Anonymous input (Other name of this service - Anonymous FTP. ). For anonymous (or guest) login to the server, instead of the username, specify the Anonymous keyword and as a password to type your email address. After that, you will be provided with access to general directories, to the data owned by the server owner. Usually, in this mode of access to the server, the user can only view directories and pump out the files to your disk. This way of working with publicly accessible FTP servers is called anonymous FTP. Some servers create special directories where everyone can also download their own files.

You can use an ordinary WWW browser to work with the FTP server. After dialing in the URL address string of the desired FTP server, your browser will connect to it and will display the contents of the remote directory.

To connect to the FTP server via a www browser, you must use the following URL recording form (Uniform Resource Locator): When using an FTP server that requires authorization :FTP: // user_name: Password @ Address_FTP Server: Port / Path_K_File When using an anonymous FTP server :FTP: // Address_FTP server / path_Fail

At first glance, such use of the browser as a FTP client is quite convenient. However, it should be noted that at the same time the method of working with the FTP server is missing the possibility of file fraud. If the connection with the server suddenly broke off and you did not have time to download the entire file (which happens quite often when reappearing large files from very remote servers), then you will have to download the entire file from the very beginning. This is one of the considerable amount of sufficiently good reasons forcing the use of a separate FTP client when working with the FTP server. The FTP client allows you to rewrite (unload, send) files to the FTP server and, that occurs a bowl, rewrite (download, receive) files from the FTP server.

Types of FTP servers

Unlike WWW servers to which almost anyone can access, there are two categories of servers in FTP. Some servers are only available for a limited circle of registered users and when you try to connect the identifier or username (Login) and password (Password). Other servers are open to everyone. They are called anonymous .

Anonymous FTP server - Open access server. The standard username for anonymous FTP servers is Anonymous, an email address is used as a password.

FileZilla.

FileZilla. - This is a free multilingual FTP client for Microsoft Windows, Mac OS X and Linux. It supports FTP, SFTP, and FTPs (FTP via SSL / TLS). On July 30, 2010, he was sixth in the list of the most popular SourceForge.net programs.

Also exist Filezilla Server - Project, related Filezilla Client. This is an FTP server developed by the same organization. It supports FTP, SFTP and FTPS (FTP via SSL / TLS).

Creating and configuring an FTP server using Filezilla Server

Creating your own home FTP server allows you to organize a convenient way to transfer data to users of the local or global network. To start it at home, you can use free software, for example, Filezilla Server . This program is endowed with all the necessary functionality and is easily adjusted.

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FileZilla Server extends to a free license, so the program distribution can be freely downloaded from the site of its developer. Before installing, you must specify the port for listening to the administrator interface and determine the FTP service start method. If you leave the default settings, the installer will select the random port and add the FTP service to the Windows autoload.

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Also before installing FileZilla Server, you must select the server startup method when loading the system. By default, all users are activated by the automatic start of the FTP service when you authorize them in the OS.

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When the installation is completed, the program will place its icon in the tray, when you click on which the server administration panel opens. In it, first of all, you should confirm the selection of the server 127.0.0.1 and the specified port, as well as, if necessary, come up with and enter the administrator password.

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The Filezilla Server setting should be started with creating one or more users and permit access to certain directories on the computer. To do this, select the "EDIT" menu item "Users" and click the "Add" button. In the window that appears, you need to enter an arbitrary name of the user, if you wish, by placing it in a specific group (it can be created in the "Edit-Groups" menu). After pressing "OK", an account will be created with the specified name, after which you can proceed to configure it.

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By default, the new user FileZilla Server is created without a password. To set it, you follow in "General" to install a tick at Password and enter it. In the same window, you can set restrictions on the number of connections for the selected user (0 - without restrictions).

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In the Shared Folders tab, you need to add a root directory of the user and select the directories to which it will have access. You can install the selected directory as root by clicking the "Set As Home Dir" button. Also in this window, you can specify the rights for the selected user on the files and directories available to it. For example, setting the ticks at the "Write" and "Delete" paragraphs in the "Files" category will give an Anonymous account and delete files in the C: \ FTP directory.

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The Speed ​​Limit tab is responsible for setting up the load speed limit and download data for a specific account. These parameters can be left unchanged.

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In the "IP Filter" window, the administrator may disable access to the FTP server from certain IP or subnets. This may be useful in the future when the unrelated users loading illegal content or inconvenience in other methods are detected.

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In general server settings, extending to all accounts, you can go from the "Edit - Settings" menu. Most of the parameters, in particular, the speed limits, the "black list" IP, SSL and Autoban initially can be left as it is. Pay attention to the "Passive Mode Settings" item that allows you to enter the domain name of the server instead of IP. This will be useful at a dynamic address varying each time connecting to the network.

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A free domain name can be registered, for example, using the DYNDNS service.

To give users the ability to exchange data with the FTP server, you need to tell them the address and account data for the entry. All their actions will be displayed in the Main Filezilla window.

FTP client

FTP client

FTP client - File Transfer Protocol (letters. "File Transfer Protocol" - a program to simplify access to the FTP server. Depending on the destination, it can either provide the user with easy access to the remote FTP server in the text console mode, taking over only the operation for sending user commands and files, or display files on a remote server as if they were part of the user's computer file system, or both. In the last two cases, the FTP client assumes the task of interpreting the user actions in the FTP protocol commands, thereby allowing the ability to use the file transfer protocol without familiarizing with all its wisdoms.

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Partial examples of using the FTP client can be:

  • Publication of site pages on the web server web developer
  • Dropping music, programs and any other data files by the usual internet user. This example is often not even realized by many users as using an FTP client and protocol, since many public servers do not request additional data to authenticate users, and Internet browsers (also being FTP clients) are downloading files without additional questions.

Sales

In the simplest user (but with the most comprehensive) case, the FTP client is an emulator of a file system that is simply on another computer. With this file system, you can make all the usual action user: copy files from the server and to the server, delete files, create new files. In some cases, it is also possible to open files - to view, launch programs, edit. It is necessary to consider only that the opening of the file implies its pre-downloading to the user's computer. Examples of such programs can serve:

  • Internet browsers (often work in read-only mode, that is, do not allow you to add files to the server)
  • Many file managers, such as: Windows Explorer, WinSCP, Total Commander, Far, Midnight Commander, Krusader
  • Specialized programs, for example: FileZilla
  • Online customers working with which is carried out through any Internet browser, for example: Ftponline.ru

Thanks to the prevalence of the FTP protocol, simple (from the point of view of implementation) FTP clients are practically in each operating system. However, using these customers requires the use of console skills, as well as the knowledge of the protocol commands to communicate with the server. So in Windows such a utility is ftp.exe. In many Linux builds there is also an FTP utility.

Access rights and authorization

The file system on the remote server, as a rule, has access rights settings for various users. For example, only some files may be accessible to anonymous users, there will be no need to know about the existence of other users. Another group of users can be available other files or, for example, in addition to the rights to read files, it may also be given to record new or updating available files. The range of access rights options depends on the operating system and the software of each specific FTP server. Typically, share the rights to view the contents of the folder (that is, the ability to get a list of files contained in it) to read the file (s), to write (create, delete, update) file (s)

To authorize the FTP server, when connecting to a FTP client to it, requests a user and password from the last. Most of the FTP clients, in turn, request this user's data in an interactive mode. There is also another way to specify this data by including them in the FTP Server URL. So, for example, in a string

** FTP: // Vasya: [email protected]**

  • FTP: // - Note that we use the FTP protocol
  • Vasya - username
  • : - User name and password separator
  • Key - Password
  • @ - authentication information separator and server address
  • FTP.example.com - FTP Server Address

There are no cases when such a method for specifying the username and password is the only one that supports the FTP client.

Examples of FTP clients

Browsers

The simplest primitive FTP clients are web browsers and Windows Explorer. To access the FTP server in their address bar, it is enough to enter FTP: // Server Name (for example FTP://ftp.drweb.com/). Web browsers and conductor allow you to view the contents of FTP servers and download files from them. However, using a browser, you will not be able to download a file or folder to the FTP server, and Windows Explorer does not support the files in the event of a connection breaking. The most important thing is that the browser allows you to just click on the link and immediately download the file, although sometimes It happens and not download, but download it, and not even one file, but a lot. Therefore, the browser is not worth viewing as a serious FTP client. Therefore, it is better to use specially intended for this program to work with FTP. Some of them are sharpened to work only with FTP, others are entire software complexes and in addition to connecting to FTP servers allow you to solve a huge number of everyday computer tasks.

Total Commander and other similar

FTP clients are also built into popular file managers, for example, Total Commander. Typically, file managers allow you to work with the FTP server just like with regular disks of a local computer, although, of course, with some restrictions that are specified by the server administrator (this may be, for example, a ban on deleting files for all other than moderator). But here there are not enough some opportunities, for example, the same task planner. Although for most users of Total Commander, there is still a very successful version of the FTP client at the expense of the built-in viewer, which will allow you to learn what it is worthwhile, as well as due to the ability to compare the contents of folders and files on the FTP server and the local computer.

Core ftp pro

You can find this program on the Internet at www.coreftp.com, the size of the installation distribution is slightly less than three megabytes. There is a free trimmed version, but we will consider full, professional. Core FTP has a pleasant and understandable user interface, supports encryption and work on SFTP and SSL protocols, integrates into popular browsers as a replacement of FTP clients built into them. It is possible to pump files directly between two sites, as well as the built-in ability to create backup data copies, including their archiving, password protection and sending to the FTP server. For advanced users there are support for the command line.

FileZilla.

This FTP client is distinguished by complete free and open source texts, as well as cross-platform (i.e., he knows how to work under different OS). Supported protocols: FTP, SSL, SFTP. FileZilla has a multilingual user interface, quite comfortable and understandable. There is support for jumping and downloading files having a size of more than 4 GB, as well as a built-in site manager. In addition, Filezilla is considered one of the most reliable and fast FTP clients. You can find it at Filezilla-Project.org, the size of the distribution for Windows is about 2.6 MB.

FTP Commander.

FTP Commander is not the most famous, but in its own way a good client for FTP. In the World Wide Website His website: www.internet-soft.com. Distribution size - from half to two and a half megabytes, depending on the version. For its capabilities in Pro version, it resembles a client built into Total Commander. But the Deluxe version supports SSL, TLS, SSH, PGP protocols, multi-threaded injection, automatic renaming if duplicate is in the file list, and some other useful features.

Cute FTP Pro.

This FTP client is considered one of the best, if not the best of all that only have on the planet. A pleasant and very understandable user interface, a built-in password manager, SSL, SSH and OpenPGP support, automation tools (job scheduler, backup creation tool, tool for creating podcasts in the form of RSS audio streams). The program has built-in HTML editor and site manager, it is possible to record and subsequent macros. So Cute FTP is a very useful and powerful FTP client. You can find it in the World Wide Web at www.globalscape.com/cuteftppro, the size of the installation distribution program is about seven and a half megabytes.

Ftprush.

Another very good commercial FTP client, located on the Internet at www.ftprush.com. The size of its distribution is about four and a half megabytes. Among its features, I would like to note a pleasant and simple user interface, which, by the way, is generally characteristic of the programs of this class, as well as the support of data compression on the fly, which is designed to save money spent by the user to jump files from the Internet. There is also a task scheduler in the program, an embedded scripting password-made engine to automate the user actions, as well as the built-in cache directories that accelerates their viewing. SFTP, FTPS, SSL, TFTP are supported, as well as, which is important for Russian-speaking users, unicode encodings are supported (including UTF-8).

SmartFtp.

On the Internet, this client can be found at www.smartftp.com. Distribution size of this program from about three to six megabytes. In the list of "regalia" (or rather, the capabilities of the program, the authors indicate the following items: support for TSL / SSL, support for IPv6, data compression "on the fly", support UTF-8, the ability to pump files directly between two servers, remote file editing, built-in Downloading Planner, Backup Creation Tool, Work Support from Command Line and Other Features, More or less standard for FTP clients. The program interface is a comfortable, beautiful and fairly ordinary.

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