Local network - what is it? How to create and configure a local network. Connecting computers into a local network. Organization of user work in local computer networks What does a local computer mean?

There are programs, or rather, assemblies of programs (platforms) that can emulate the operation of virtual hosting on an individual (home) computer. This means that by installing one of these platforms on your machine, you can work on creating a website without going online. Creating and testing a website on a local server can be approached in different ways. Some people cannot release a website without a local version, while others make websites directly on real hosting sites. But be that as it may, local server technologies exist, there are many software assemblies for developing websites on home machines, which means we will talk about them, talk about them, write articles and reviews on this site.

To get into the topic of this section, let’s look at the structure of the global network from a home computer to any website. To visualize words, let's take a simple picture.

As you can see, from the home machine to the site, which is on shared hosting, information passes through quite a lot of sections, the so-called network nodes. You can easily see all these nodes before any site on your computer by running a command, for example, ping.

The general idea of creating a website on a local computer

The general idea of creating a website on a local computer is simple. Instead of a long network from the computer to virtual hosting, local hosting is installed on the computer, and you, as a user, work not with remote hosting, but with hosting (server) installed on your actual disk.

This is not surprising if you remember what it is virtual hosting or dedicated service. In fact, these are also computers, only very “big”. It is also placed on them software, with which the hosting (server) is managed.

Local server software builds

To simplify a little, the main software assembly with which hosting can operate is an operating system, a web server, a database management system and a programming language. In such an assembly, various web servers (Apache, Nginx), various operating systems (Windows, Lunix), various DBMSs (MySQL, PostgreSQL, MariaBD, InnoDB) and various programming languages (PHP, Perl) can be combined.

For a local machine, software assemblies of local servers are labeled by the first letters of the programs included in the assembly. For example, LAMP is a Linux+Apache+MySQL+PHP build, and a WAMP build is Windows+ Apache+MySQL+PHP.

In conclusion, I would like to note that if there are ready-made assemblies, then someone assembled them, which means you can install all the assembly programs separately on your computer and configure them to work together to emulate the work of hosting. There are also articles on this site about this.

Network called a single complex that includes a geographically dispersed system of computers united in unified system means of communication using communication equipment, software and protocols to solve information, management, computing and/or other problems.

The local network(Local Area Network - LAN) connects computers and peripheral equipment within one or more adjacent buildings. The network organized within the office is also local. The main purpose of a local network is to share the resources of one computer with another computer(s). Thus, a local network allows you to share files, applications, peripherals(printers, scanners, etc.), work with by email, use the system instant messages, participate in electronic conferences, etc.

The principle of construction (configuration) of network connections is called topology. Based on topological characteristics, local networks can be represented by three basic topologies: common bus, star, ring.

By topology common bus(backbone) all computers are connected to one cable (Fig. 118).

At the ends of the cable there are terminators(energy absorbers) that serve to prevent signal reflection. The message sent by the workstation is distributed to all computers on the network. Each machine checks who the message is addressed to, and if it is addressed to her, then processes it. In order to exclude the simultaneous sending of data, either a “carrier” signal is used, or one of the computers is the main one and “gives the floor” to the other stations.

Rice. 118.

Advantages of such a construction are:

- simple structure, which allows you to expand the network by adding an additional number of computers;
- low cost of implementation;
- the network is easy to set up and configure.

Flaws:

- low efficiency due to loss of productivity with the addition of new workstations;
- network problems, such as a cable break, completely block the operation of the entire network.

This topology is used in local networks with architecture Ethernet(technology and architecture for building large local computer networks). Data transmission in networks of this type is possible via coaxial cable at a speed of 10 Mbit/s (10Base-5 and 10Base-2 standards), twisted pair cable (10Base-T standard) and fiber optic cable (10Base-F standard).

In a topology like "star"(Fig. 119) each computer is connected by a cable (twisted pair) to hub(habu). A hub allows workstations to be connected in parallel so that all computers connected to the network can communicate with each other.

The workstation from which data needs to be sent sends it to the hub, which determines the recipient and gives him the information. At a given time, only one machine on the network can send data; if two packets arrive at the hub at the same time, both packets will be rejected and the senders will have to wait a random period of time to resume data transmission.

Advantages topologies:

- failure of one computer does not affect the operation of the entire network as a whole;
- good network scalability - easy to connect a new computer;
- easy troubleshooting and network breaks;
- high network performance.

Flaws star topologies:

- failure of the central hub will result in the inoperability of the network (or network segment) as a whole;
- high cable consumption, especially if the hub is not located in the center of the topology;
- the finite number of workstations in a network (or network segment) is limited by the number of ports in the central hub.

Rice. 119 .

In a network with a topology "ring"(Fig. 120) all nodes are connected by communication channels into an unbreakable ring through which data is transmitted. All data on this network is transmitted from one station to another in one direction. Each computer works as a repeater, restoring and amplifying signals.

TO merits Ring topologies include:

- ease of installation;
- almost complete absence of additional equipment;
- the possibility of stable operation without a significant drop in data transfer speed under intense network load.

Flaws Ring topologies are as follows:

- if one computer fails or the cable breaks, the ring “breaks”;
- connecting a new computer leads to a short-term network shutdown;
- complexity of configuration and setup;
- Difficulty in troubleshooting.

Rice. 120.

Exists two main types of local networks, based on the computer connection scheme: client/server and peer-to-peer network.

IN networks server based(rice. 121) there is a dedicated server- specialized computer, which controls the use of resources shared between workstations, for example external memory, printers, databases, etc.

Rice. 121.

There are several types of servers, in particular:

- mail server - controls the transmission emails between network users;
- file server- manages the creation and use information resources local network, including access to its databases and individual files, as well as their protection. For example, when working with a test editor, the file is stored on a file server and will be loaded into the memory of your computer;
- application servers- controls the operation of the local network when performing any application tasks. Examples of this kind of tasks can be: ensuring communication with other local and/or telecommunication systems, collective use of printing devices, etc.;
- proxy servers- can store frequently requested information in cache memory on a local disk, quickly delivering it to users without re-accessing the Internet;
- print servers- allow all computers connected to the network to print documents on one or more shared printers. In this case, there is no need to equip each computer with its own printing device. In addition, by taking on all the worries about printing documents, the print server frees up computers for other work.

The advantages of a network with a dedicated server include, in particular, the following.

1. High performance, since a high-performance computer is installed as a server, with significant amounts of internal and external memory, powerful central processor etc.
2. Support for a significant number of workstations.
3. The ability to implement access control, which means that you can limit the user’s access to various resources, which increases the security and protection of data.
4. Opportunity backup storage, since the data is stored on the server.

There is no dedicated server in a peer-to-peer network (Fig. 122), all computers

equal rights, i.e. each user personally decides what data on his computer to provide for public use.

To organize constant communication between computers on a peer-to-peer local network, they are combined into work groups.

Working group- this is a group of people (for example, employees of an organization) who are engaged in one project. Computers for everyone working group constitute a separate segment.

LAN segment- part of the network cable, limited routers(a device designed to provide access to remote local networks and the Internet, as well as to organize communication between networks and their interaction), repeaters, terminators and other additional devices.

A separate group includes print servers with several conventional printers connected to them, which at the same time acquire network capabilities and can work over the network, regardless of whether they support this mode of operation. Typically print servers have LPT connectors. Such servers are used in large organizations, but at home it is quite enough to have one printer on a computer connected to a local network so that all computers in the workgroup have access to it. All of the above can be expressed in a single term - "shared access to resources."

Rice. 122.

Thus, a peer-to-peer network is convenient to use in teams of up to ten people, taking into account the fact that the network is not expected to scale in the near future.

The advantages of a peer-to-peer network include:

1. Cheapness of building a network due to the use shared printers and other peripheral devices.
2. No special software required and powerful computer as a server.
3. High qualifications are not required when installing and administering the network.

The disadvantages include:

1. Low security, since insufficient security of one workstation can lead to infection of other computers with viruses.
2. Quite low productivity, since no special requirements are imposed on the workstation.
3. Users must have sufficient qualifications to solve problems that arise during operation.

Currently, in any store, office or enterprise it is impossible to work quickly and fully without a local network into which all employee computers are connected. LAN is also used at home or other places where there are multiple computers.

To organize user work on a local computer network, a number of requirements must be met, including:

1. A network cable must be connected to the computer.
2. As additional device network card installed.
3. The connection to the local network has been configured.

Other settings can be made even by an inexperienced user. In particular, in order to set the workgroup name, which other computers, say, in your office or organization have. To do this, click on the button Start, go to item Computer, by clicking the right mouse button go to the menu item Properties. The window shown in Fig. will open. 123.

Rice. 123.

Let's pay attention to the bottom part of the window, labeled as Computer name, domain name, and workgroup settings. There is a link on the right Change settings by clicking on which the user can change the computer name and workgroup name.

Another setting is related to providing shared access to folders. To make a folder visible on the network, you must perform the following steps:

1. Find the folder to which you are going to share access, suppose the folder Documentation.
2. Right-click on it.
3. Go to item Specific users and in the window that opens (see Fig. 124) press the button General access.

Rice. 124.

After that general access the folder will be open to all users on the local network. If you need to deny access to a folder to which it was previously granted, then you should follow the steps described above, only when you complete step 3, click on the button Terminate access.

At working together on a local network, other users can use your printer, scanner, fax, etc. In order to provide access to your resources, you must complete the following steps:

1. Enable the feature sharing printer. To do this, run the following command Start/Control Panel/Network and Internet/Network and Sharing Center. On the left side of the window, select Change Extra options general access.
2. Select the desired profile. Activate option Enable file and printer sharing. A similar situation is shown in Fig. 125.

Rice. 125.

3. Run the command Start/Devices and Printers. Right-click on the desired device, select Printer properties.
4. Go to tab Access and check the option Share this printer. The network name of the printer is also set here.
5. Click on the button OK.

1. Define the concept of “network”? What is the main purpose of local networks?
2. What is topology?
3. Draw a diagram of how computers are connected using a common bus topology. What are the advantages and disadvantages of this topology? What are terminators used for?
4. Draw a diagram of how computers are connected using a star topology. List the advantages and disadvantages of this topology. What does the hub provide?
5. Draw a diagram of how computers are connected using a “ring” topology. Explain the advantages and disadvantages of this topology.
6. Draw a diagram for constructing a local network based on a server and describe it.
7. Name the types of servers and give them characteristics.
8. List the advantages of a dedicated server network.
9. Draw a diagram of a peer-to-peer network and describe it.
10. For what purposes are working groups created? What is a LAN segment?
11. Name the advantages and disadvantages of peer-to-peer networks.
12. Determine what type of network is used in your computer classroom. Draw its diagram.
13. Together with your teacher, try to graphically construct a diagram of the networks of your educational institution.
14. What are the requirements for organizing user work on a local network?
15. Show practically how to set a workgroup name and share folders on a specific computer.
16. Demonstrate how you can provide access to local computer resources to other users.

Workshop

Concept of system administration

With the increasing use of computers, systems administration is becoming a key area in more and more organizations. The administrator must understand his system, know its users and their occupation. The main thing in administration is the ability to plan, since in the conditions of creation, modernization and expansion of systems, an attempt to improvise and develop network solutions on the fly is doomed to failure.

Network Administrator ( System Administrator) - a specialist whose responsibilities include performing the following main functions:

- installation of the operating system and application programs;
- description of the information environment;
- setting up the operating environment;
- setting up network printing;
- network monitoring and management of network resources;
- archiving and restoring network data.

Let's look at them in more detail.

Installation(English, installation) - the process of installing software on a computer. During the operating system installation process, the administrator must answer a number of questions interactively.

Description of the information environment- includes the following actions:

- creation of user directories;
- assigning access rights to directories and files;
- assigning attributes to directories and files.

Setting up the operating environment includes:

- installation of configuration files for workstations;
- development of system and user procedures for connecting to the network;
- workstation management.

Setting up network printing suggests description:

- print objects (queues, printers, print servers);
- print forms (paper size);
- configurations of print jobs.

Network monitoring- assessment of its performance and reliability characteristics. Using special software packages you can implement:

- monitoring of file servers and network segments;
- management of a file server, hubs, workstations.

Archiving and restoring network data. IN case of large volume

of archived data, all computers involved in the archiving process must have a high-speed (100 Mbit/s or higher) connection to the local network. Otherwise, the archiving process may take considerable time.

In addition to the above functions, the system administrator must know the basics of information security. This concept includes the protection of information located on personal computers and servers of the enterprise local network, from unauthorized access, intentional distortion and damage. This concept also includes anti-virus protection of the local network and individual computers from virus attacks, all kinds of Trojan programs, malicious macros and software bookmarks.

In addition to the listed professional knowledge, the administrator must have communication skills, non-conflict, patience, know the basics of psychology and conflict management, since he is the link between computer technology and those who work on it.

The risks of the Internet are associated solely with its uncontrollability. Being a colossal source of information, the Internet does not divide it into good and bad or useful and useless. In addition, the Internet is ultimately a paid resource, i.e., the consumption of information from it must be paid for by someone.

The main disadvantages of uncontrolled use of the Internet in organizations are the following:

- user access to harmful and useless information, which entails distraction from the work process;
- penetration of viruses and worms into the enterprise network;
- cost overruns due to non-work-related Internet activity of users.

To effectively combat the risks described above, you need a system that performs three critical functions:

1.Accounting for the consumption of Internet resources. If employees know that their every “step” on the global network is monitored, this will reduce traffic and prevent misuse of the institution’s funds. It will be possible to easily find out which resources are visited by users during working hours.
2. Internet access control. In order to be able to specify which employees can have access, when and where. This will reduce lost work time and improve safety.
3.Network protection from information leakage, hacker attacks, network viruses and worms. This component is necessary to ensure the security of the enterprise network.

Differentiation of access rights in the network

Provide information security allows differentiation of user access rights to working documents and annexes. Each employee gets the opportunity to work only with those resources that he needs, while all documents are protected from accidental or intentional viewing or modification.

Currently, there are a number of programs on the market that provide, in particular, control and management of Internet access, protection of users and enterprise networks, traffic accounting, antivirus protection and content filtering of web traffic. Conventionally, they can be divided into several categories:

Free programs, which can be downloaded from the Internet. But, as a rule, such programs are designed to solve individual problems. There are programs for collecting statistics, but they do not have the ability to process data according to various parameters. Conversely, there are programs for limiting resources that do not have statistics collection functions, etc.

An example is the BWMeter program, designed for graphically displaying and counting traffic that is transmitted over a local network. Using the utility, you can count transmitted packets, as well as find out where and from where they are sent, through what protocol and to what port.

Paid solutions on the protection and control of corporate information can be purchased on CDs on the Internet. Professional solutions of this kind from well-known foreign manufacturers, as a rule, meet all the above requirements, but are expensive. This category includes programs such as Kerio WinRoute Firewall, Ideco ICS Standard Edition, UserGate proxy server, Windows Svr Ent 2008.

Hardware and software systems to control Internet connection. They are convenient because their functionality is focused specifically on the end user, i.e., companies of any level, meet all requirements and are easy to use. Their main advantage is that you do not need to select equipment and install software. A hardware-software complex or simply a server connects to the network, is configured to its characteristics and works. An example is the Internet Control Server 2.x software package, which is installed on a computer and separates the corporate network from the Internet, controlling all information flows and accounting for traffic between the institution’s network and the Internet.

On the tasks of delimiting access rights in the network can be attributed:

1. Distribution of users into groups and creation account for each group and user separately.
2. User authorization.
3. Prohibition of access to certain objects.
4. Setting restrictions on the consumption of Internet resources.

In order to distribute users into groups, it is necessary to create a user structure using an analysis of the organization, for example, highlight all departments, think through the characteristics for identifying user groups. For example, the following structure is possible: planning and financial department, accounting department, personnel and office management department, etc. For dedicated departments, you need to create groups and create users within them, or do it differently - create users without groups. In principle, there is not much difference here. The only advantage of creating groups is the ability to track consumption for the group as a whole. Using access profiles, you can easily set the same access rights for individual users, not combined into groups. Of course, for groups there is no need to create an access profile.

How does user authorization work? When opening a new browser window and requesting a resource from the Internet, the user receives a window asking for a login and password. In this window you must enter your username and password given user, which were given to it during creation. If the login and password are correct, the user gains access to the Internet.

For implementation prohibiting access to certain objects you need to create a locking system that works according to the following example:

User 1

User 2

User 3

With this structure, “user 3” will be denied all three resources (www.yandex.ru, www.google.com and www.auto.ru), “user 2” will have only the top two - Yandex and Google, “User 1” will have access to any resource except www.yandex.ru.

It is also worth noting that each of the users from the example above must have explicit permission to access any (!) resources. There will be no disruption as the rules of higher groups will also apply. That is, taking this into account, the example will look like this.

All users (www.yandex.ru is prohibited)

User 1 (all allowed)

User 2 (all allowed)

User 3 (all allowed)

The sequence in which rules are added affects the priority of the rules (the higher the rule is located, the higher its priority over the others).

The network administrator may need to set a certain set of prohibiting/permitting rules for a whole set of users who are located in different groups. So that he does not have to manually add this set rules separately for each user, it is possible to create a so-called access profile with the appropriate set of rules and then add it to the list of access rules for each individual user.

As already mentioned, the Internet is a paid and public resource. Therefore, savings are of great importance Money educational institution and, in addition, the restriction bandwidth channel for specific users in order to more equitably distribute channel capacity among all users. To do this you need to set restrictions on resource consumption Internet.

In this regard, the following characteristic is introduced: the maximum volume of traffic consumption (quota), if exceeded, the network administrator can take various punitive measures.

By tracking the dynamics of traffic consumption by users, the network administrator can determine the average maximum traffic volume, if exceeded, it is possible, for example, to disconnect the user who has violated the rules from the Internet without warning.

Not a single network administrator of an educational institution will allow ordinary users (students) to carry out the above-described functions of delineating access rights in the network during practical classes. However, on a regular school or home computer you can consider, in particular, account creation process. The fact is that quite often situations arise when several people work on one computer, and in this case it is possible to make sure that each user has their own Windows settings. In addition, you can give some users the ability to install new software, while denying others. It is also possible to prohibit the use of certain programs on the computer.

There are three types of accounts. Each type gives the user different options for controlling the computer:

- regular user accounts are intended for everyday work;
- administrator accounts provide full control over the computer and are used only when necessary;
- Guest accounts are intended for temporary access to the computer.

In other words, when you log into Windows using the normal

account can perform the same actions as an administrator account, but Windows may require an administrator password to make changes that affect all users on the computer (for example, installing software or changing security settings).

To create a new account, run the command Start/Control Panel/User Accounts and Family Safety. The window shown in Fig. will open. 126.

Rice. 126.

Let's select an item Adding and removing user accounts. IN

in the window that appears (Fig. 127), select the item Create an account.

Rice. 127.

Rice. 128.

Next you need to specify the account name and access rights (Administrator or Regular access) which the owner of the account being created will have to have (Fig. 128), and click the button Create an account.

Your account has been created and now you need to configure it. To do this we perform double click mouse on the created account.

In the window shown in Fig. 129, there are the following points:

1. Change the account name.
2. Create a password.
3. Changing the pattern.
4. Set up parental controls.
5. Changing the account type.
6. Managing another account.

Rice. 129.

Let's comment on some of them. First, after creating an account, you need to create a password for it (Fig. 130). Using a password increases system security. Field Enter a password hint may not be filled out. After entering the password and duplicating it, click on the button Create a password.

Rice. 130.

Set up parental controls. A new feature in Windows 7 allows you to set the time when the user (child) can use the computer, as well as determine what games and programs will be available to him. By using parental controls Can:

- limit the time spent by the user (child) at the computer. You can limit the amount of time children are allowed to log in. For each day of the week, you can set aside a time to log in to the system, even if the user works at the computer, the system will automatically log out;
- set a ban on access to certain games. You can control access to games, choose the appropriate age rating, what types of content should be blocked, and set whether or not to allow or deny access to specific or uncategorized games;
- establish a ban on the user (child) using certain programs.

For implementation prohibiting access to certain objects, in particular, for Internet resources, you should install the additional module “Family Safety”, located at http://windows. microsoft.com/ru-RU/windows-live/essentials-other-programs (Fig. 131). However, in this case you will need to first obtain an identifier Windows Live ID in the Windows Live service at http://www.home.live.ru.

By installing the core components of Windows Live on your computer, you can enhance your experience with photos, videos, and email. Basic Windows components Live is free and includes Windows program Live Messenger, Photo Album and Film Studio. With your Windows Live ID you can access everything Windows services Live, including Hotmail, SkyDrive and Messenger, with one login.

Rice. 131.

After registering and installing the Family Safety component, options will become available for filtering and blocking Internet resources that, in your opinion, are undesirable for the user to visit. They include the following sections:

1. Web filter.
2. Create an action report.
3. Contact management.
4. Requests.
5. Time restrictions.
6. Game restrictions.
7. Program limitations.

The settings will be available at http://familysafety.live.com if the system administrator first enters a Windows Live ID and password.

After entering the password, a window with the above parameters will appear on the screen (Fig. 132).

Let's look at some of the parameters.

Web filter. With its help, you can control what types of websites users (children) can view and track the sites they visit (Fig. 133). In particular, you can allow visiting web resources only from the white list, added by the administrator (parent), block adult sites, allow or prohibit communication on social networks.

Rice. 132.

Rice. 133.

Web filter lists. With their help (Fig. 134), you can manage the list of websites that are allowed or blocked for the user (child). By compiling a list of specific sites in advance, the administrator (parent) can allow or block access to them.

Time restrictions. In a special dialog box (Fig. 135) you can select the time when the user (child) is allowed to use the computer. In the clock grid, white rectangles indicate allowed hours of access to the computer, and blue rectangles indicate prohibited hours.

Rice. 134.

Rice. 135.

Game restrictions. Each game has its own rating, i.e. the rating of the category of people for which it is intended, for example, the game is allowed for children over 3 years old, over 6 years old, over 10 years old, etc. In accordance with these assessments, one or another category of games can be allowed/prohibited. The window for setting game restrictions is shown in Fig. 136.

Rice. 136.

Application restrictions. The corresponding window (Fig. 137) will list the programs installed on the computer, from which you can select those that are not allowed to be used.

Connecting your computer to the network

So, we have considered issues related to the differentiation of access rights on the network and on the user’s computer, and we have gained the concept of system administration. However, we assumed that the local network was already configured and the computer with the operating system installed was connected to the local network. Now it's time to meet connecting your computer to the network and settings associated with this process. It should be noted that such actions will most likely be prohibited by the educational institution’s network administrator, so you can view the general progress of connection work on your personal computer without changing its settings in any way.

First, the computer connecting to the network must have LAN card, secondly, a network cable must be connected to it and, thirdly, an agreement must be concluded in advance with the network service provider.

By executing the command Start/Control Panel/Network and Internet/View network status and tasks, the user will see the window shown in Fig. 138.

Rice. 138.

Typically within a few seconds after turning on Windows computer 7 defines and configures parameters home network. Otherwise (in our example), the straight line connecting the SERGEY-VAIO section (this computer) - Multiple networks would be crossed out with a red cross. If a red cross appears on the site Internet(Fig. 139), this means that there is no connection to the Internet.

Rice. 139.

If you place your mouse pointer over the red cross, the message “Click here to troubleshoot” will appear. After clicking the mouse it will start Troubleshooting Wizard. However, those recommendations that Master will be issued at the end of the diagnostic process; only an experienced user can help. Even if you forcefully disconnect the network cable, Master will not display the message “Your network cable is disconnected”, but will inform you that you need to restart the modem.

In order to configure the computer’s connection to the network, in the window Network and Sharing Center(see Fig. 138) select item Internet Options/Connections. A similar situation is presented in zis. 140. Next, click the button Add VPN...

Rice. 140.

What is a VPN? Various computer companies Often the problem arises of combining several local networks that are located at a great distance from each other. In addition, there is the problem of connecting remote users and providing them with the necessary protection from unauthorized access. In the event that a company uses its own or leased communication channels or telephone lines, then this is a rather expensive solution that only large and very successful companies can afford. That is why, in order to reduce the cost of data transmission, virtual network technology (English: Virtual Private Network VPN) was developed.

The main feature of this technology is that on top available network In a connection that has already been established, a special channel is organized. This channel allows you to provide very high and reliable protection of the information that is transmitted through this channel (the so-called tunnel) from the subscriber to the provider. For these purposes it is used PPTP protocol(English: Point-to-Point Tunneling Protocol), a point-to-point tunnel protocol that allows a computer to establish a secure connection with a server by creating a special tunnel in a standard, unsecured network.

Let's return to the VPN connection settings. By pressing the button Setting, should be entered Username: Password And domain. The window shown in Fig. 141.

All data must have been previously issued to the user by the network service provider. Next in the window Properties: Internet button should be pressed Network configuration. A window will open Configuring local network settings(Fig. 142), in which you will need to check the box Use a proxy server for LAN connection. When finished, press the button OK.

Next, you need to manually set/clarify the parameters network settings. To do this, in the window at Start/Control Panel/Network and Internet/Network Connections(Fig. 143) you need to double click on the icon LAN connection.

Rice. 141.

Rice. 142.

Rice. 143.

This action will cause a window to appear in which you should click the Properties button. The Local Area Connection - Properties window will open, shown in Fig. 144.

Rice. 144.

Rice. 145.

Next, from the list of components you need to select the option Internet Protocol Version 4 (TCP/IPv4) and press the button Properties. The window shown in Fig. 145 in which the options should be activated Obtain an IP address automatically And Obtain the DNS server address automatically.

Each computer on the network must have its own unique IP address, determining its location on the Internet. IP addressing is 32-bit digital system, designed to identify network computers in the Internet. Consists of four sets of numbers, where each number can range from 0 to 255, and is separated from the other values by a dot, e.g.

Domain name system similar to phone book. The user finds the name of the person or the name of the organization with which he wants to contact - indicated next to phone number. Similarly, a computer accesses DNS (Domain Name System) using the name of another computer or domain, and the name server issues an 1P address corresponding to this name.

A domain (area) name allows a person to work not with digital addresses of computers, but with familiar symbolic names (website addresses). The domain name is read from left to right from minor domains to domains top level(in order of increasing importance).

For example, the domain name krf.ane.ru has three components called levels and separated by dots:

ru- Domain name 1st (top) level;

ane.ru- 2nd level domain name (second level domain in the w zone); krf.ane.ru- 3rd level domain name (third level domain in the ane.ru zone). In terms of purpose, the following domain designations are accepted:

Cell - for commercial sites;

Info - for companies or sites providing information;

Net - for telecommunications companies or companies doing business online;

Org -- for non-profit organizations;

Biz - zone for business sites as an alternative to the.cell zone;

Ru, .de, .tk, .cn, .us, .ca, etc. - domains of different countries (geographical). Let's go back to the settings. Being in the window shown in Fig. 145, go to the tab Alternative configuration(see Fig. 146). Values for IP address, DNS server, etc. issued by your network service provider.

Next in all open windows button pressed OK. Settings network connection computer is completed, but you should restart your computer. After the reboot, double-click on the network connection name shortcut (it is specified during setup). The window shown in Fig. will open. 147.

The username and password will be the default and will not need to be entered again. All you have to do is press the button Connection. After which the connection to the Internet is considered established and the user is taken to the home page (specified in the settings).

Rice. 146.

Test questions and assignments

Rice. 147.

1. What functions does a system administrator perform?
2. List the administrator's steps to configure the operating environment.
3. What is the network printing setup?
4. Describe the administrator action known as network monitoring.
5. What knowledge should a network administrator have in such an area as information security?
6. What are the disadvantages of uncontrolled use of the Internet in organizations? What should a system provide to reduce such disadvantages?
7. What software is used to control and manage Internet access? Give examples.
8. List the tasks of differentiating access rights in the network.
9. How does user authorization work?
10. How does the locking system work to deny access to certain objects?
11. Why is an access profile created?
12. What are the three types of accounts? Tell us about each one.
13. What steps do I need to take to create an account?
14. What is the Windows 7 feature called parental controls?
15. Tell us about such a protection option as a web filter.
16. What needs to be done in order to connect a computer to the network?
17. Show practically the sequence of actions required to connect a computer to the network.
18. For what purposes is the PPTP protocol used? What is special about VPN technology?
19. Explain what IP addressing is for.
20. Tell us about domain system names Give examples of domain names. Explain what levels a domain name consists of.

Designers and administrators often have to make changes to the operation and interface appearance of their website. And, as it happens, everything always works and is not displayed as planned - the background has moved out, the icon is too large, errors in scripts or database queries, and generally inadequate operation of the site. In such cases, you don’t want to traumatize the audience; no one likes to sit on a non-usable project where requests are delayed, fatal errors. The chance of losing some visitors during such “experiments” is very high, not to mention the risk of completely breaking the structure of work and rendering the entire system unusable.

Making a local server from a regular computer

For such cases, engineering has come up with local hosting of web servers - a completely similar technology for communicating between a website and a real server, which will allow you to test all your ideas and innovations on an offline version of your project, where there are risks of data loss and other troubles.

We have dealt with a brief description of the local location of sites, although there are many more other reasons for this.

Remains software part- is there software that can provide us with this opportunity? It should be fairly easy to install, rich in functionality and be a full-fledged tool for project management (when managing one or more sites). Yes, there is such a product - XAMPP? to make a local server from a computer.

XAMPP - assembly with ready-made tools, supports cross-platform. Everything we need to complete the task is in it, also meeting the points of multifunctionality.

Installing the program is simple and no different from the ordinary algorithm of pressing the “next” button; no complex choices will be given during installation.

The interface displays all necessary information: connected or non-functioning modules, output of operation/connection errors of certain libraries and their startup/forced stop.

Directly from the program, you can launch phpMyAdmin in your default browser, starting full-fledged administration work - through the web interface, performing the necessary operations in MySQL, just click the Admin button.

Built-in Webalizer analyzer - site performance statistics, displayed via graphs

Mercury Mail - receiving and sending mail on your computer or to others via local network

FileZilla FTP - FTP server with support for drag&drop technology and directory synchronization

All of the tools listed provide a complete simulation of a real web server, saving you money - to use local technology placing anything other than the computer and supported operating systems not necessary (xampp supports macOs and Linux), if you decide to rent a test server for your project, which will require the same payment for capacity as a regular site.

Scripting instructions in web languages such as php and JavaScript work perfectly in the local environment as embedded modules or directly in the form of executable files.

Local server - This special program, which is installed on a local (read home, that’s why it’s called LOCAL) computer, allowing web developers (webmasters) to develop websites on a local (home) computer, without the need to access the Internet. This is not even one program, but a complex of programs that perform various functions. A local server is similar to a real real server located on the Internet by the Hoster company.

What is it for? As you already know, regular HTML pages with CSS design are processed by browsers without problems. Those. If your site is created from simple web pages built on HTML and CSS, then such a site can be perfectly developed on a local computer without any servers. Just click on the html file as usual with the left mouse button and the web page opens in the browser. You have worked with the code, design, added or removed something, save, update (F5) and see the result.

But if you are developing a dynamic website created using, for example, PHP, Perl, MySQL databases, some ready-made scripts, That To test and debug such sites, you definitely need to install a local server on your computer.

For what? The fact is that such sites (web pages of sites) before being sent to the visitor in the browser, pre-processed by the server, and only then in the form of regular HTML code are given to the browser. This happens very quickly on the server side, i.e. on the Internet and visitors do not even notice such pre-processing.

For example, sites made using PHP are assembled as if from separate pieces, separate files. Let's look at a simplified diagram of such a site. As a rule, any such site (any web page) contains several main components:

Site header;

Site footer;

Menu;

Main page content (content).

When creating a website in PHP, each such piece is a separate file with the extension .php

A simplified site diagram in PHP, presented at Figure 1 below:

Figure 1. Simplified site diagram in PHP.

Of course, this is not a complete list of components (pieces); sometimes there are a lot of such pieces (files). But the operating principle is always the same. On the server, a web page is assembled from separate files (in this case, header.php, footer.php, menu.php, content.php) and the site visitor is given the finished result in the form of html code. You have already noticed that all files here have the extension .php

What is PHP?

PHP is a programming language specifically designed for writing web applications (scripts) that run on a Web server.

The acronym PHP stands for “Hypertext Preprocessor”. The language's syntax comes from C, Java, and Perl. PHP is quite easy to learn. The advantage of PHP is that it allows web developers to quickly create dynamically generated web pages. My website was created using PHP language.

So, if you want to look at the code like this PHP pages (right button, view-HTML code) then you will not notice the difference with a regular web page created in HTML. But know that all web pages with the .php extension work this way (they are assembled piece by piece from separate files).

In addition, PHP has another great feature: the PHP code script can be easily integrated into any HTML code.

On the local computer, to “assemble” and process PHP files, a local server is installed, which in this case acts as a processor.

Currently, most dynamic web pages: forums, blogs, guest books, most forms feedback, and just PHP scripts, will work on a home computer only if there is a local server.

In my practice, I use a local server called Denver (denwer). You can download and view detailed installation instructions on the official website http://www.denwer.ru/. Or on our website in the section.

With us you can do it for free. What is Zend Optimizer?

Zend Optimizer is a special utility that is used for coding and optimizing scripts ( PHP programs), encrypted using Zend Guard (scripts are encrypted in order to protect program code from plagiarism and unauthorized use). This utility allows you to optimize your code for even faster execution of scripts (PHP applications) and increases site loading speed by 40%.

To put it in “simple” language, then Without the Zend Optimizer utility installed on your computer near Denver, many scripts simply will not work, since most developers protect their software products (scripts, programs, etc.) from unauthorized intervention and theft.

Zend Optimizer is installed after installing Denver to your home computer by simply replacing the folders: denwer, home, tmp and usr, which come with this assembly.

Local server "Denver" is the original project of Russian programmer Dmitry Koterov. Therefore, everything here is in Russian, there are very detailed instructions and recommendations. Moreover, everything is absolutely free. There are educational video lessons. More Denver is called - Gentleman's Web Developer Kit.

If you plan to create dynamic websites, download, install and use.

Do I need a local server?

For beginners, I’ll start by defining the concept of “local server” - this is a server (hosting) that is located on your computer (not on the Internet) and allows you to create and configure websites on it.

I believe that it is necessary to create and further configure the site on a local server, so that then in one fell swoop you can place a fully functional site with all the settings on the Internet. And then immediately fill it with content.

This is what truly professionals in website creation do. Even if we look at people who constantly work with creating websites on various engines, we will see that almost every one of them first installs the site on a local server, then configures it, and only then transfers it to real hosting.

As an example, I’ll show you the menu from Sergei Patin’s course "Joomla 3 - professional website in one day". Look at the sequence in which the website is created.

As you can see, from the very beginning the site is installed locally, configured, and at the end the completely finished resource is transferred to hosting.

Placing a website on the Internet and then setting it up when you need to promote it is unwise.

What if you already have a website? Do you need a local server?

Let's imagine the situation that you already have a website and you are a very avid techie, that is, you like to always delve into all sorts of technical issues and constantly experiment with something.

So, you already have a website and there are already some visitors on it. Although not a large number, they exist. Put yourself in their shoes.

You go to a website and constantly see that the owner of the site or blog is constantly changing something. It changes the location of blocks on the site, the structure, and sometimes the design is new every day. Would you like this? So visitors wouldn’t really like this situation.

Developing, setting up websites, as well as creating designs on a website that is already posted on the Internet is, at a minimum, not professional. Not to mention the fact that it has a very negative impact on its development and approval in the eyes of search engines and your audience.

Therefore, you need to do all such things on your local computer.

Now we will start installing it, after which you can install it on local computer your website and do whatever you want with it. Visitors will not see these frauds, because... This is your personal computer and no one has access to it. And after you bring everything to its final state, you can easily transfer it in a completely finished form to a real website.

By the way, I also talk about the importance of a local server when creating a blog in my mind map “Plan for creating a quality blog from Konstantin Khmelev,” which you can get by leaving your 1st comment.

Let's move on to the installation process itself.

Install a local server on your computer

The local server is a program. Therefore, you need to download it. We will use the Denwer web server for this.

Go to the official website program and click on the big button.

After clicking, you are prompted to select the program version. Choosing a version old PHP 5.2 and press the button Download.

In the next window we need to enter the data where the link to download Denwer will be sent. Enter your real data and click on the “Get download link” button.

After clicking the button, you will immediately receive an email with a link to download the program. The sender and subject lines of the letter will be as follows (see screenshot below).

After downloading, in the location where you saved the program you will see an installer that will look like this.

To start installing the local server, run the installer.

It asks us if we want to install the base package? We agree.

The unarchiving of the data will begin and will proceed very quickly.

After unpacking the data, the installation of the local server will begin, which will be carried out on the command line. Immediately when it starts, we will be asked to close the browser.

Automatically, when the command line appears, the browser will open with a message that you must close the browser to continue or cancel the installation.

You should also close other browsers if the command line installation will not continue.

After closing all Internet browsers, installation will continue. You just need to follow the prompts that the command line gives.

To continue the installation, press Enter.

I'll install it in another place. In my case it's a disk E folder host.

In the next step, press Enter again.

The next step is to select a virtual disk letter. By default, the program prompts you to select drive Z, since this letter is the last in the English alphabet and it is unlikely that any drive is occupied by it.

I'll leave it like that. You can enter another letter, but make sure that no drive is occupied by it.

After selecting and entering the letter, press Enter to continue installing the local server.

After copying is complete, you must select the Denwer launch option.

There are 2 launch modes, but the program itself recommends choosing option 1. That’s what we do. Enter the number 1 into the command line and press Enter.

launch;
stops;
reboot.

We need these labels. Therefore, enter the letter Y and press Enter.

This was the last step in installing the local server, after which the browser will automatically open with the message “Denwer installed successfully”, and it will also be written that Denwer works with the same ports as Skype.

Therefore, if you have Skype installed, then do what is written in the browser window.

It will also create the desktop shortcuts that we wanted so much.

Start Denwer - start Denver;
Stop Denwer - stop;

All. Our local server is installed. Now all that's left to do is check it out a little. Run it and see if ours is really virtual disk, which will act as a local server, will start.

Before we launch, let's go to the directory where we installed Denver and see what's there.

Since I installed on drive E in the host folder, now there should be such a folder on my drive.

The way it is. And inside the folder there should be the Denver files themselves. We go inside the folder, where we should see the following picture.

There are files. This means everything was successfully copied during installation.

Now let's check whether Denwer itself starts. Let's use the shortcut to launch.

After launching the shortcut, 2 will flash quickly command lines. When they disappear, 2 shortcuts will appear on the taskbar.

If such shortcuts appear, then Denwer is running. A virtual disk with the letter Z should also appear in my case. In your case, with the letter you assigned. Also, this disk should be named similarly to the disk in which you installed Denver itself.

As you can see, there is drive "E", which I installed in, as well as drive "Z", which appeared after launching Denver. They have the same names. Both disks are named "Local Disk". Only the letters are different.

If we go to the virtual disk (Z), we should see the same files and folders in Denver that we looked at earlier.

All friends. This completes the installation of the local server. Now you can start creating a website on it and do any manipulations with the site.

In the next article I will show. You will also find a detailed article with images and a video tutorial there.

By the way, about the video lesson. If someone doesn’t understand something from the text version, then here’s a video lesson that I specially recorded for you.

With this I will say goodbye to you. I look forward to your comments and any ideas for new blog articles. If something doesn’t work out or you have any questions, write them in the comments.

All the best.

Best regards, Konstantin Khmelev.