If there are several computers in one room or building, the users of which must jointly solve some tasks, exchange data or use common data, then it is advisable to combine these computers into a local network.
Here are some examples:
If the computers of your organization are connected to a network, then the exchange of documents between employees is reduced to copying or moving operations.
It is possible that a printer is connected to one of the computers. Then, thanks to the local network, users of other computers can print documents on it from their computer.
A local area network is a group of several computers interconnected by means of cables (sometimes also telephone lines or radio channels) used to transfer information between computers.
The icon of the Network Places folder is displayed on the Desktop, designed to work with the local network.
Connecting computers to a local network requires that each computer has a network adapter installed, or, as it is often called, a network card. In modern computer models, the network adapter, as a rule, is already built into the motherboard.
Each computer on the network is also called a workstation. Each workstation has its own name and belongs to a workgroup. You need to know the computer name in order to find it on the local network.
To view the computer name and the name of the workgroup, you need to right-click on the My Computer icon, select the Properties item from the context menu, and in the window that opens, go to the Computer Name tab.
Figure 5.1.
Viewing LAN Resources
To see which folders on the network are shared, double-click the My Network Places icon on the desktop. If there is no Network Neighborhood icon on the Desktop, follow the steps Start --Network Neighborhood.
In the window that opens, on the left, select Show workgroup computers. On the right side of the window, icons with the names of network computers will be displayed. To view the resources of the selected computer, you need to double-click on its icon (Fig. 5.3).
To search for a computer on the network, you need to execute the following commands in sequence: Start - Search - Computers or people - Computer on the network. Enter the computer name in the search bar and click the Find button.
How to organize access to the resources of your computer on the local network
Folder sharing settings for network users are opened via the folder context menu.
To allow other network users to open and read files from a specific folder on your computer, follow these steps:
Select the folder that you want to make available to others, right-click on it and select Sharing and Security from the menu that opens. The Properties dialog box will open (Fig.5.5);
Click the Sharing tab, and in the Network Sharing and Security section, check the Share this folder box;
If you want other users to be able to modify the files in this folder, that is, open full sharing, check the Allow files to be modified over the network check box and click the Apply button.
After that, other network users will be able to connect your folder and use it as their local one.
Sharing a network printer
A network printer is a printer that is shared with individual users.
To make your printer available to other users, you need to do the following: run the Start --Printers and Faxes command, a dialog box will open with icons for all printers and faxes that are connected to your computer. Find the icon of the printer you want to share, right-click on it and select Share from the context menu that opens. In the window that opens, go to the Access tab
(Fig. 5.6) and set the switch to Share this printer. In the activated text field, you can enter the name of this printer, under which it will be seen by all other network users. Click on the OK button.
To connect the printer from a remote computer, follow these steps: Run Start --Printers and Faxes. Double-click the Add Printer icon.
The Add Printer Wizard will start. Click the Next button in the wizard window. In the next dialog box, set the radio button to Network printer connected to another computer. Click the Next button. In the next dialog box, set the radio button to Browse Printers and click Next. In the dialog box that opens, in the list of printers that appears, find the one you want to use, select it and click the Next button. After that, you will be prompted to install printer drivers. In all other windows, feel free to click on the Next button and in the last one, on the Finish button.
Now you can print documents on a network printer from any computer. You can connect any number of such printers, one of which will be assigned as the main one (by default, documents for printing are sent to it), and the rest as additional ones.
Ministry of General and Vocational Education
Sverdlovsk region
State BUDGET educational institution
Secondary vocational education
Sverdlovsk region
"ASBESTOV POLYTECHNICUM"
Message
by discipline "Information technologies in professional activity"
topic: local and global computer networks
Completed:
group student: ODL 2-1
A.V. Marusik
Checked:
teacher
information disciplines
E.V. Maksimova
"____" __________ 201_
______________________
Asbestos
INDEPENDENT WORK
Form of independent work:
Working with the library catalog, self-selection of the necessary literature;
Finding the necessary information on the Internet
Abstract writing.
Abstract on the topic: "Local and global computer networks"
1. Introduction
2. History of network development
3. The principle of building computer networks (network structure - figure)
4. Local computer networks
5. Network topologies (Figure and explanation of each topology)
6. Corporate and regional networks
7. Global computer networks
8. Addressing on the Internet
9. Conclusion
10. List of information sources
Abstract structure requirements:
1. Title page (the title page is the first page of the abstract or test paper);
3. Introduction (in the introduction, the problem is briefly formulated, the purpose and objectives of the abstract or test work are indicated);
4. The main part (consists of several sections that describe the essence of the abstract or test);
5. Conclusions or Conclusion (in the conclusions, an assessment of the results of the work is given);
6. List of sources of information (contains a list of sources referred to in the main part of the abstract or test).
Requirements for abstracts:
1. Abstracts and tests are drawn up on sheets of A4 format (210x297), the text is printed on one side of the sheet with one and a half intervals;
2. Font parameters: typeface - Times New Roman, style - normal, font size - 14 points, text color - auto (black), hyphenation - automatic;
3. Paragraph parameters: text alignment - to the width of the page, first line indent -12.5 mm, line spacing - One and a half;
4. Page margins for the title page: top and bottom margins - 20 mm; right and left margins - 15 mm;
5. Margins of all other pages: top and bottom margins - 20 mm, left margin 30 mm, right margin - 15 mm;
6. The title page indicates the name of the educational institution, the topic of the essay, the name of the academic discipline, group, form and course of study, full name. author, full name supervisor (verifier), place and year of work;
7. Each structural part must be started with a new section from the next page (Insert/Page break);
8. Pages are numbered in Arabic numerals, following continuous numbering throughout the text. The serial number is placed at the top of the page, on the right;
9. The page numbering starts from the title page, but the page number is not indicated on the title page and on the “Contents” page, the numbering is indicated from the number 3 (from the third page);
10. The text of the main part of individual tasks is divided into sections, subsections, paragraphs and subparagraphs;
11. Sections, subsections, paragraphs, subparagraphs are numbered in Arabic numerals;
12. Sections should be sequentially numbered within the material presented and indicated by Arabic numerals, do not put a dot at the end of the section number;
13. Headings (headings of the 1st level) of each structural part of an individual task (for example, content, introduction, etc.) and headings of sections of the main part should be placed in the middle of the line and printed in capital letters without underlining and without a dot at the end;
14. Illustrations must be placed immediately after the first mention of them in the text or on the next page;
15. The table is located immediately after the text in which it is mentioned for the first time or on the next page;
16. Tables are numbered with Arabic numerals in order within the section;
17. Notes are placed in the text, if necessary, to clarify the content of the text, table or illustration;
18. Formulas and equations are placed immediately after their mention in the text, in the middle;
19. The list of sources of information can be placed in the order the source appears in the text, in alphabetical order of the names of authors or titles, and in chronological order.
INTRODUCTION
Internet- a global computer network covering the whole world. If earlier the network was used exclusively as a medium for transferring files and e-mail messages, today more complex problems of distributed access to resources are being solved. About two years ago, shells were created that support the functions of network search and access to distributed information resources, electronic archives.
Internet Once exclusively used by research and academic groups whose interests ranged from access to supercomputers, it is becoming increasingly popular in the business world.
Companies are enticed by speed, cheap global connectivity, ease of collaboration, affordable software, and the unique database of the Internet. They see the global network as an addition to their own local networks.
At low service costs (often only a flat monthly fee for the lines or telephone used), users can access commercial and non-commercial information services in the US, Canada, Australia and many European countries. In the archives of the free access of the network Internet you can find information on almost all areas of human activity, from new scientific discoveries to the weather forecast for tomorrow.
Besides , Internet provides unique opportunities for cheap, reliable and private global communications around the world. This turns out to be very convenient for firms with their branches around the world, multinational corporations and management structures. Usually, the use of infrastructure Internet for international communication is much cheaper than direct computer communication via satellite or telephone.
Currently Internet is experiencing a period of recovery, largely due to the active support from the governments of European countries and the United States. The United States annually allocates about $1-2 million to build new network infrastructure. Research in the field of network communications is also funded by the governments of Great Britain, Sweden, Finland, and Germany. However, public funding is only a small part of the incoming funds. the "commercialization" of the network is becoming more and more visible (it is expected that 80-90% of the funds will come from the private sector).
History of network development
In 1961, the Defense Advanced Research Agency (DARPA), on behalf of the US Department of Defense, began a project to create an experimental packet transmission network.
This network, called ARPANET, was originally intended to study methods for providing reliable communication between computers of various types. Many methods of transmitting data over modems were developed on the ARPANET. At the same time, protocols for transmitting data on the network - TCP / IP - were also developed. TCP/IP is a set of communication protocols that define how different types of computers can communicate with each other.
The ARPANET experiment was so successful that many organizations wanted to get into it to use it for daily data communications. And in 1975, ARPANET evolved from an experimental network to a working network. The Defense Communications Agency (DCA), now called the Defense Information Systems Agency (DISA), assumed responsibility for network administration. But the development of ARPANET didn't stop there; The TCP/IP protocols have continued to evolve and improve.
In 1983, the first standard for TCP / IP protocols was released, which was included in the Military Standards (MIL STD), i.e. to military standards, and everyone who worked on the network was required to move to these new protocols. To facilitate this transition, DARPA approached the leaders of Berkley Software Design to implement the TCP/IP protocols in Berkeley(BSD) UNIX. This is where the union of UNIX and TCP/IP began.
After some time, TCP / IP was adapted into a common, that is, a public standard, and the term Internet came into general use. In 1983, MILNET spun off from ARPANET and became part of the Defense Data Network (DDN) of the US Department of Defense.
The term Internet began to be used to refer to a single network: MILNET plus ARPANET. And although the ARPANET ceased to exist in 1991, the Internet exists, its size is much larger than the original, as it connected many networks around the world. Figure 1.1 illustrates the rise in the number of hosts connected to the Internet from 4 computers in 1969 to 14 million in 1997.
Source: http://www.seoap.ru/knowledge/internet1/art1/id~5/
The principle of building computer networks (network structure - figure)
Modern network technologies have contributed to a new technological revolution. The creation of a network in an enterprise, a firm favors a much higher process of data exchange between various structural divisions, speeding up workflow, controlling the movement of materials and other means, increasing and accelerating the transmission and exchange of operational information.
The creation of local area networks and the global single network of computers is given the same importance as the construction of expressways in the sixties. Therefore, the computer is called the "information superhighway." Emphasizing the benefits that the use of networks will bring to all users, experts talk about information "at their fingertips".
A computer network is a collection of computers and various devices that provide information exchange between computers on a network without the use of any intermediate storage media.
The whole variety of computer networks can be classified according to a group of features:
territorial prevalence;
Departmental affiliation;
Information transfer rate;
Type of transmission medium.
By affiliation, departmental and state networks are distinguished. Departmental ones belong to one organization and are located on its territory. State networks are used in government structures.
According to the speed of information transfer, computer networks are divided into low-, medium- and high-speed
According to the type of transmission medium, they are divided into coaxial, twisted-pair, fiber-optic networks, with the transmission of information via radio channels, in the infrared range.
Computers can be connected by cables, forming a paj-personal network topology (star, bus, ring, etc.).
It is necessary to distinguish computer networks to a network of terminals (terminal networks). Computer networks connect computers, each of which can work autonomously Terminal networks usually connect powerful computers (mainframes), and in some cases PCs, with devices (terminals) that can be quite complex, but their work is either impossible or impossible outside the network, or completely loses its meaning. For example, a network of ATMs or cash desks. They are built on completely different principles than computer networks, using other computer technology.
In the classification of networks, there are two main terms: LAN and WAN.
LAN (Local Area Network, local area network, LAN) - local networks that have a closed infrastructure before reaching service providers. This term can also be used to refer to a small office network, AND a network of the level of a large plant occupying several hundred hectares. Foreign sources even give a close estimate of about six miles (10 km) in radius; use of high-speed channels.
WAN (Wide Area Network) is a global network covering large regions, including both local area networks and other telecommunication networks and devices. An example of a WAN is a packet-switched network (Frame Relay), through which various computer networks can “talk” to each other.
The term "corporate network" is also used in the literature to refer to the combination of several networks, each of which can be built on different technical, software and information principles.
The types of networks discussed above are closed networks, access to them is allowed only to a limited number of users for whom work in such a network is directly related to their professional activities.
Local computer networks
When working on a personal computer offline, users can exchange information (programs, documents, and so on) only by copying it to floppy disks. However, moving a floppy disk between computers is not always possible and can take quite a long time.
The creation of computer networks is caused by the practical need to share information between users working on computers remote from each other. Networks provide users with the opportunity not only to quickly exchange information, but also to share printers and other peripherals, and even work on documents at the same time.
A local network unites computers installed in one room (for example, a school computer class consisting of 8-12 computers) or in one building (for example, several dozen computers installed in various subject rooms can be combined into a local network in a school building).
The local networkunites several computers and allows users to share the resources of computers, as well as peripheral devices connected to the network (printers, plotters, disks, modems, etc.).
In small local networks, all computers are usually equal, that is, users independently decide which resources of their computer (disks, directories, files) to make publicly available over the network. Such networks are called peer-to-peer.
If more than 10 computers are connected to the local network, the peer-to-peer network may not perform well. To increase performance, and also to provide greater reliability when storing information on a network, some computers are dedicated to storing files and software applications. Such computers are called servers, and the local network server based network.
Network hardware. Each computer connected to the local network must have a special board (network adapter - Fig. 4.2).
The main function of the network adapter is to transmit and receive information from the network. Currently, EtherNet type network adapters are most commonly used, which can network computers of various hardware and software platforms (IBM-compatible, Macintosh, Unix computers)
 |
| Rice. 4.2. Network adapter |
Computers (network adapters) are connected to each other using cables of various types ( coaxial, twisted pair, fiber optic). To connect laptops to a local area network, a wireless connection is often used, in which data is transmitted using electromagnetic waves.
The most important characteristic of local networks, which is determined by the type of network adapters and cables used, is the speed of information transfer over the network. The speed of information transfer over a local network is usually in the range from 10 to 100 Mbps.
Network topology. The general scheme for connecting computers in a local network is called network topology. Network topologies can be different.
The option of connecting computers to each other, when a cable runs from one computer to another, connecting computers and peripheral devices in series with each other, is called line bus(Fig. 4.3).
If a separate cable from one central node is connected to each computer, then a local area network of the type "star".
Typically, with this connection scheme, the central node is a more powerful computer.
The advantage of a "star" local network over a "linear bus" local network is that if the network cable on one computer fails, the local network as a whole continues to function normally.
Providing access to computer resources. In the Windows operating system, the user of any computer connected to the network can provide access to their drives, folders, or files. Users working on other computers can then use the provided resources.
Granting access to computer resources
1. In the context menu of the object (disk, file, folder), select the command Access.
2. On the dialog panel that appears Properties: select tab Access.
 |
Use the switches to set Shared resource, and select the type of access ( Read Only, Full, Password Defined).
In a text box For full access: you can enter the password required to access this resource.
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1. Protection of information from unauthorized access
information computer unauthorized access
Unauthorized access to computer resources is the use, modification or destruction of programs and data by a person who does not have the right to do so.
An attacker can bypass protection against UA in two ways:
login under the guise of a legal user;
disable protection.
Bookmarks can be used to perform NSD. These are programs with potentially dangerous consequences:
hide their presence in the system;
multiply or transfer their fragments to other areas of memory;
save fragments of RAM;
change information on disk or in memory.
According to the place of introduction, bookmarks are divided into:
connected to elements of the operating system;
connected to application programs;
imitating programs with password entry;
disguised as toys.
Conceptual bookmark models:
Observer. The bookmark is introduced into the system, intercepts I / O information and writes to disk.
Trojan horse. The bookmark simulates a computer crash. An attacker gains access to information under the guise of repair.
Distortion. The bookmark distorts information.
Garbage collection. The bookmark examines the remnants of information, backups and deleted files.
The seriousness of the NSD problem is evidenced by the fact that in 1993 in Russia several dozen cases of bookmarks were recorded in banks, intermediary and information firms.
In 1994, an interdepartmental commission on information security was created under the Security Council of the Russian Federation.
The main channels of information leakage:
Electromagnetic radiation.
Secret manual or viral copying.
Theft of magnetic media.
Computer theft.
To block these channels, it is necessary to shield the premises from electromagnetic radiation, organizational measures (similar to virus protection), software protection.
Integrated data protection based on software includes the solution of the following tasks:
data encryption;
protection from research by programs that decrypt data;
computer control for bookmarks;
linking programs to a specific computer;
reliable user identification (identification);
search and destruction of stolen information.
2. Encryption of information
For encryption, modern cryptography methods, special information exchange protocols, and non-standard methods of data storage are used. The software block that performs data encryption and decryption is built into the executable module, which is protected from investigation by debuggers, disassemblers, and from unauthorized copying.
A debugger is a program that allows you to execute the program under study in a step-by-step mode, viewing the contents of memory and processor registers at each step.
A disassembler is a program that allows you to get the text of the program from the executable module in machine codes.
Protection from research involves a special style of programming that complicates the analysis of executable code.
Encryption includes two elements - an algorithm and a key. An algorithm is a sequence of actions to transform information. The key is a specific value of the encryption algorithm parameters. Knowing the algorithm, but not knowing the key, it is almost impossible to decrypt the data. With the same result it is possible to have a key without an algorithm.
3. Basic encryption algorithms. Substitution (replacement) method
The method is based on the tabular coding principle. Each character is associated with another character. It is possible to build a more complex table, where several codes are assigned to symbols, depending on the frequency of use. Then the codes in the ciphertext are distributed evenly and are more difficult to decipher.
An example of an encryption table.
This method is convenient for encrypting texts. Permutation Method
This method involves the mutual permutation of characters. With a file size of N bytes, the total number of mutual permutations is
N! = N*(N-1)*(N-2)*…*3*2*1.
This method is useful for encrypting binary files such as graphics and executables. In this case, it is not necessary to rearrange each byte - it is enough to make several permutations in key places of the software product - this will reduce the encoding time.
Byte Encryption Algorithms
Bytes of the message itself can be used as a key.
Examples: each byte is encrypted by adding it to the previous byte. Or: the current value of the byte is added to the byte spaced by the specified number of bytes.
In its purest form, the algorithm is very weak, because the key is contained in the encrypted file itself. This method is used in combination with others.
coding book
Each ciphered word corresponds to the location of this word in an art book, one copy of which is kept by the coder, the other by the one who decrypts. The weak link here is the key, i.e. book. With regard to a PC, this method can be modified by considering computer ROM codes or codes of a software package used by the transmitting and receiving parties as the encoding book. In this case, the code of each character of the source text is assigned to the position of this code in the ROM.
Public Key Encryption
This method uses two keys - secret and public. Knowing the public key, it is impossible to calculate the secret from it.
The ciphertext S is obtained from the plaintext F by transforming
where a mod b is the remainder of the integer division of a by b.
Decryption occurs according to the rule:
The public key is the numbers (x, n).
The secret key is the numbers (y, n).
The numbers x, y, n are formed according to certain rules, so knowing (x, n) it is very difficult to calculate (y, n). The cipher will be strong enough if the key length is at least 150 digits.
Main characteristics of encryption methods:
encryption algorithm;
key renewal period;
key length;
cryptographic strength, i.e. resistance to decryption by an attacker. Usually determined by the time period required for decryption.
4. Protection of information from unauthorized access by identification
Identification is
identification, identification, identification, authenticity.
building a model of an object based on observations of its inputs and outputs.
the operation of determining the identity of a user or user process, necessary to control access to information.
the procedure for comparing the presented characteristics with the reference ones.
User access to various classes of information should be carried out using a password system, which includes:
regular passwords;
real locks and keys;
user identification tests;
computer, diskette, software identification algorithms.
The password typed on the keyboard can be peeped by the movement of the fingers or with the help of a virus bookmark. The key to the lock can be lost, stolen or copied without the owner noticing.
User identification tests are more reliable. Special devices allow for automatic identification by voice, retinal pattern, fingerprints, etc. Software identification includes mouse signature recognition and keyboard handwriting recognition.
5. User identification by keyboard handwriting
The analysis of keyboard handwriting can be carried out in two ways: by typing a key phrase and by typing free text. Both methods involve setting mode and identification mode.
In the setting mode, the reference characteristics of the user's typing are calculated and stored. In the identification mode, the user is identified.
To set up, the user types a given phrase on the keyboard several times. The system remembers the time between pressing letters, as well as slowing down and speeding up when typing individual words. As experience shows, this is quite an individual characteristic.
When typing a passphrase, this phrase is always the same. To enter free text, this text is generated each time randomly from a previously prepared set of words.
Over time, handwriting can change, including keyboard. Therefore, handwriting standards should be updated regularly.
6. User identification by mouse painting
To analyze the mural, a sequence of screen coordinates of the mural line is used. It is convenient to use the following quantities as characteristics of this line:
the number of dots in the painting line on the screen (in graphics mode, a VGA-type display is a field of 640 by 480 dots);
painting line length;
number and position of line breaks;
number and position of segments (line, arc, circle, etc.).
7. Other ways to identify the user
People estimate the number of letters in words differently, the length of the line on the screen, remember random numbers and letters.
An example test might be as follows: several lines of random length are displayed on the screen for several seconds. The user for some time must enter from the keyboard estimates of the length of the lines. This test will check:
keyboard handwriting;
attention and accuracy.
Most people, when called for a minute to the management or to the phone, leave the computer without completing work with a mandatory exit and access denial. In the case of unauthorized access to completely open information, it is possible to identify an attacker with software that constantly monitors the operation of the computer and detects deviations from the usual course of action, as well as recognizing the user by keyboard handwriting and the manner of working with the mouse during the entire session of work.
Computer identification
Each PC has its own hardware features that cannot be changed by software. For example, this is the PC architecture, i.e. a list of devices and their characteristics - the number and parameters of drives and hard drives, the type of video adapter, etc. The program can read this data in previously known ROM cells. Features of the ROM are the date of creation and the manufacturer. ROM contains BIOS programs for working with computer devices - disks, screen, printer, etc.
Special devices are used to enhance protection. The device contains logic chips, ROM and connects to a computer through a serial or parallel port. This device is called an electronic key. During operation, the program polls this device. If it does not respond, then there is no key, and the program stops working or does not work correctly, with errors.
Disk identification
A defect is created in a certain place on a diskette using a scalpel or a laser. The program remembers the position of defective sectors. A protected application attempts to write information to bad sectors when it starts up. An unauthorized, defect-free copy on a floppy allows a normal write to be made anywhere on the floppy. If the program detects the fact of illegal copying, the protection mechanism is activated.
Another way to protect a floppy disk is non-standard formatting: changing the numbering of sectors, the length of sectors, the number of tracks.
Software environment identification
Some features of a PC are created and modified by software:
meta of physical location of protected files on the disk;
the presence on the computer of certain drivers, files, application software packages;
launching a certain sequence of commands before calling the protected package;
modification of operating system programs;
creation of labels on the disk that are not copied by conventional means;
placement in the body of the program in encrypted form of data about the author of the program and a specific buyer.
Software module identification
Checking the conformity of the program to some standard establishes the facts of making changes to the executable module. These can be the consequences of the work of viruses and bookmarks, or hacking attempts, i.e. disabling software protection. A software module is a sequence of binary codes. To identify a program, you can calculate the checksum of a file or its fragment, the frequency of use of certain codes in a file, etc.
Placing a special code sequence outside the file boundary is not detected by the usual means and is not copied by the COPY program.
Example. Files on disk are stored as a sequence of clusters. Clusters are blocks of 512 bytes on a floppy disk and 4 kilobytes on a hard drive.
Information about which files form which clusters are stored in FAT. If the last cluster in the chain is not completely occupied by a file, the remaining space is not used and is not copied by the COPY command. There you can write a label.
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System software that ensures that the operating system is loaded immediately after the computer is turned on. The bootloader is launched by the BIOS software stored in the computer's ROM (English basic input / output system "basic input / output system")
The central part of the operating system that controls the execution of processes, the resources of the computing system and provides processes with coordinated access to these resources. The main resources are CPU time, memory, and I/O devices. File system access and networking can also be implemented at the kernel level.
A set of possibilities, ways and methods of interaction between two systems for the exchange of information between them. If one of the interacting systems is a person, they often talk only about the second system, that is, about the interface of the system with which the person interacts.
Command line interface: instructions to the computer are given by entering text lines (commands) from the keyboard. Graphical user interface: Program functions are represented by graphic elements on the screen. Conversational interface: for example, Search Gesture interface: touch screen, steering wheel, joystick, etc. Natural language interface used in intelligent systems, the user "talks" to the program in his native language. Neurocomputer interface: responsible for the exchange between neurons and an electronic device using special implanted electrodes.
Before the end of the download, Windows prompts you to enter a "username" and password (Fig. 8.6).
Rice. 8.6. Entering the network password
In doing so, the following actions are performed:
1. The default name shown in the text line Username , is the computer name entered during setup. If desired, you can change the input name to something else, such as your name.
2. Enter in the line Password password to prevent other users from accessing your copy of Windows. When entering a password, the letters are replaced with asterisks so that no one spies the password. If you will not use a password, leave this line blank.
3. Click the button OK . If you press the button Cancel , Windows Professional will not allow you to boot the operating system. Those. without the correct username and password in Windows, the user's work is impossible.
If you were not prompted to enter your network password when you started Windows, and there is no icon on the Windows desktop network , this means that the computer is not configured for the network.
If you are offline or want to log on to the network with a different username, follow the procedure below.
For Windows:
1. Press the button Start and select the item Ending a session....
2. Press the button OK.
3. After the window appears Entering the network password follow the steps in this section.
Working with a document or program located on another computer is practically no different from working with similar resources on your own computer.
Rice. 8.7. IconMy network environment on Windows.
In Windows 2000, this icon is called My network environment(Fig. 8.7). Then double-click on the icon of the desired computer. If the computer you want is not in the list, use the icon Whole network. Open this folder to view all workgroups that are part of the complete network your computer is connected to. (If you're only connected to your workgroup, you'll only see that one workgroup.) When you open the workgroup folders, the names of all the computers that make up each workgroup are displayed. Double click on the folder you are looking for.
For each computer, only those resources are visible to which the owner or system administrator has allowed access.
Organization of network access to computer resources
Installing File and Printer Sharing for Microsoft or NetWare networks allows you to make computer resources (programs, documents and other files, and printers) available to other users. Other users can connect to and use the computer's shared resources. To share individual files, share the folder containing them.
Organization of access to files and printers of the computer
1. Press the button Start and select the item Control Panel on the menu Setting.
2. Double click on the icon Net.
3. Select a tab Configuration in the dialog window Net.
4. Press the button Access to files and printers. The dialog box shown in Fig. 8.9.
Rice. 8.9. Organization of access to files and printers
5. Check the appropriate box.
6. Press the button OK.
Organization of protection of network resources
There are two modes of access to computer shares:
1. Access at the resource level. Selecting this access mode allows you to organize password protection network resources from unauthorized access. Any user who wants to access a share must know the password assigned to that share. Such protection is useful in small networks.
For each shared resource, Windows provides three types of permissions:
Only reading. At this level, anyone accessing the resource can only copy, open, and view files. Files cannot be forwarded, modified, renamed or deleted, nor can new files be added.
Complete. This level provides full access to resource files and allows you to do all operations with files.
Defined by a password. This level allows the assignment of separate passwords for reading and for full access.
To grant or deny public access to a resource, follow these steps:
1. In a folder My computer select the resource to share or deny.
2. Menu File or in the context menu (called by the right mouse button), select the item Access... If item Access missing, it is necessary to organize access to files and printers (see section 4.4.1).
3. In the dialog box that appears Properties(Fig. 8.10) set the switch to position Shared resource to allow sharing of a resource or location Local resource- for the ban.
Rice. 8.10. Assigning a password to drive D
4. Set the switch Access type into position Defined by password.
5. In the relevant fields Password(for read and/or for full access) enter the password for accessing computer resources.
6. Press the button OK.
7. Enter the password again in the window Password confirmation.
Granting access to the printer is done in a similar way. Use the folder to select the desired printer. Printers (Start -> Settings -> Printers).
2. Access at the user level. When using this protection mode, access to resources is granted depending on the rights received by the user from the network administrator, for example, Windows NT/2000. Each user is identified on the network by the name assigned to him along with the rights by the administrator.
When using this access method on Windows 98 stations, you can grant the right to use station resources to individual users or groups formed by administrators of one or another level.
This makes protection more flexible, since the Windows NT/2000 administrator can grant a number of additional rights in addition to full and read access to folders. Domain User Names and Groups UC, created by the Windows NT/2000 network administrator, are shown in fig. 8.11.
Rice. 8.11. Adding Station Resource Users
Granting the appropriate rights to the selected user group is performed by pressing the button Read only, Full access or Special. Special rights are more diverse and are determined by the capabilities of the OS of the network server.
Folder properties My documents when using user-level security, are shown in fig. 8.12. Only five users have access to this resource, and each of them has its own access rights.
Rice. 8.12. Assigning Shared Access to the My Documents Folder
