The wi-fi network is working. How to create and configure a home WiFi network

Wi-Fi is now the most popular data transmission technology in wireless computer networks. The name is a trademark that belongs to the wi-fi alliance. The technical description of the technology is contained in the IEEE 802.11 standard.

Previously, Wi-Fi was decoded as "Wireless Fidelity" wireless accuracy, but now it is believed that Wi-Fi is decrypted in no way and just looks like a Hi-Fi word play, that is, high quality.

In order for a manufacturer to name his Wi-Fi equipment, he must submit it for inspection to the Wi-Fi Alliance. This company verifies that the equipment complies with the IEEE 802.11 standard. And the right to use the Wi-Fi trademark is given after the Wi-Fi alliance makes sure that the equipment is fully compliant with IEEE 802.11.

For comparison, for ethernet, such a check is not performed, the manufacturer can create equipment that works according to the 802.3 standard and its modifications and call it an Ethernet switch

Wi-Fi location in

Wi-Fi, like Ethernet, is located at the physical and link layer, and the link uses two sublayers, the MAC media access control sublayer and the LLC logical link control sublayer.

Wi-Fi operating mode

Wi-Fi can work in two modes, most often the infrastructure wifi mode is used in which there is wireless equipment, the so-called access points that connect to a wired network and then to the Internet. Now, Wi-Fi is most often used to connect to the Internet. Therefore, the infrastructure mode is the most popular.

Another connection option is also possible, a peer-to-peer network, where computers interact without any access points, directly with each other.

Wi-Fi and Ethernet

Wi-Fi technology is very similar to Ethernet technology, one might say, adapted in a wireless environment. For addressing wifi is used in the same way as in Ethernet.

For data transmission, a shared medium is used, as in classic Ethernet. Only in classic Ethernet is the signal transmitted over the cable, while in wifi electromagnetic radiation (radio air) is used.

The frame format at the LLC level is the same for Wi-Fi and Ethernet, IEEE 802.2. In practice, this means if you use wireshark to capture packets that go over the network, then regardless of whether your frame came from Ethernet or from Wi-Fi, its format will be the same. Although in the process of transmission over the wireless medium at the MAC layer, Wi-Fi uses a different frame format.

Wi-Fi Physical Layer Standards

There are several different options for implementing Wi-Fi, they are described in 6 standards. The very first 802.11 standard was adopted in 1997 and had a speed of 1 or 2 Mb / s, Ethernet at that time could transfer information at a speed of 10 Mb / s. The modern wifi standard 802.11ac was adopted in 2014, the maximum transmission speed is more than 6 Gb / s.

Now Wi-Fi is used for data transmission - electromagnetic radiation or radio air, but in the first version of Wi-Fi infrared radiation was used, now this method is used in TV remotes.

But since the second generation of the 802.11b standard, only electromagnetic radiation has been used. The two frequencies used are 2.4 and 5 GHz. Frequencies in this range can be used without licensing. However, other devices also operate in the same range, for example a microwave oven, and this interferes with the transmission of the Wi-Fi signal.

Signal presentation

Modern wi-fi standards use Orthogonal Frequency Division Multiplexing (OFMD) for data transmission. Data is transmitted in parallel at different frequencies.Although the frequencies in the picture overlap each other, the OFMD method can reliably identify signals.

Channels in the 2.4 GHz band

Channels in the 2.4 GHz band are used for data transmission 14 channels, the picture lists their frequencies. The channels are slightly shifted relative to each other, but still partially overlap.

Thus, the number of wi-fi networks that are in the same place is limited by the number of channels; there can be no more than 14. If more than 14 networks work in the same area, they will not have enough channels. This situation is known as "Wi-Fi jungle" and it is quite common, for example, in residential buildings where a Wi-Fi router is installed for Internet access in each apartment.

Wi-fi channel width

Wi-Fi can use channels of different widths. Channel width is the difference between the maximum and minimum frequency at which data can be transmitted. The wider the channel, the more qualitatively we can transfer data, therefore, the higher the data transfer rate.

In the 802.11n standard, it became possible to use channels with a width of 40 MHz and thereby increase the transmission speed. The latest 802.11ac WiFi standard can use 80 MHz and 160 MHz channel widths. However, support for 160 MHz channels is provided if possible and at the request of the manufacturer.

Spatial flow

In the 802.11n standard, it became possible to use multiple antennas for transmitting and receiving data. This feature is also used in the modern standard.

If we have several antennas, then we can use several spatial streams - this is a signal that is transmitted from one antenna to another.

If we transmit several spatial streams in parallel, then the data transfer rate increases. This uses a special signal coding method called MIMO - multiple transmission and multiple reception.

Example: we have 3 antennas at the transmitting station and three at the receiving station. Each antenna at the transmitting station (Tx) sends its own spatial stream, thus we increase the transmission rate by 3 times. At the receiving station, all three antennas receive 3 spatial streams, and using the mimo coding method, they are able to separate them and improve the signal quality for each separate spatial stream.

Speed \u200b\u200badaptation

In Ethernet, the equipment speed is fixed, it will be the same for all devices on the network. Weifai also allows you to change the speed depending on the signal quality. If the signal quality is high, the speed increases, and if it is low, the speed decreases. In order to increase or decrease the speed, Wi-Fi changes several parameters:

• Different channel widths can be used from 20 MHz to 160 MHz.
• Supports a variety of modulations that allow data transmission at different rates and reliability
• It is possible to change the interval of data between characters that are transmitted via Wi-Fi.

A table that shows different speed options for one spatial wifi stream. The lowest speed of 6.5 Mb / s is obtained using 20 MHz BPSK BPSK and 800 ns symbol spacing. The fastest speed of 866 Mb / s is obtained using IAM with 256 states, a 160 MHz channel and 400 ns symbol spacing.

The data is presented for one spatial stream, if your access point and your station have multiple antennas, then you can use multiple spatial streams and thereby further increase the transmission rate.

The user differs from the consumer in that he has an idea of \u200b\u200bthe things to which he resorts. Anyone who reads these lines can consider himself a user of wireless Internet using Wi-Fi technology. If he knows how the network works. For those who do not belong to such people, we suggest that you familiarize yourself with the material, which tells about the principles of Wi-Fi wireless communication, its features, advantages and disadvantages.

History

We will not embark on a journey of half a century or more, we will bypass all prototypes and developments. The "father" of Wi-Fi is John O'Sullivan, an engineer at the Australian Astronomical Laboratory. Under his leadership in 1997-1998. there was something that is used by almost the whole world. After 2 years, the first IEEE 802.11a standard was registered, which is still widespread.

Due to the high level of wave interference, IEEE 802.11b was quickly developed, but it did not solve the main problem. The waves also scattered and overlapped. However, this was corrected by dividing the operating frequency range into channels.

After 10 years of development, the IEEE 802.22 standard appeared, which supports data transmission over distances of up to 100 km in a straight line. For 2019, 18 IEEE 802.11 standards have been developed with different bandwidths and operating frequencies.

The term "Wi-Fi" is an allusion to Hi-Fi, and is not deciphered in any way. However, it is generally believed that the word comes from Wireless Fidelity - wireless accuracy.

About the work of wireless technology in video format:

How does it work?

Wi-Fi is a wireless data transmission technology, wireless the local network (WLAN). The principle of Wi-Fi operation is the transmission of encrypted signals by means of microwave waves (microwave waves) over short (tens of meters) distances. The network diagram consists of at least two elements: an access point and a client.

There are client-client schemes - without the use of access points.

The access point broadcasts the identifier (SSID, network name) via special data packets 10 times per second at a speed of 100 Kbps. This is theoretically the lowest wireless bandwidth.

How does the Wi-Fi network work? When it enters the coverage area and detects a signal, the client device concludes that it is possible to connect to it (the difference in technologies can become a hindrance). The transmitter may not transmit its identifier, then the network will be invisible to clients. You can connect to it only by entering the SSID and password if it is protected.

If there are 2-3 networks with identical SSIDs in one zone, the receiving device connects to the one with the best signal.

The access point in home Wi-Fi networks is primarily a wireless router. He and clients must work in the same mode (frequency, signal modulation). Let's consider the example of distributing the Internet in a private house.

The router receives traffic through a network cable, converts it into radio waves and spreads them "over the air" in the form of ultra-high frequency radio signals with certain parameters. The receiver "catches" these waves and decodes them (decrypts, extracts information from them, which is encoded by the carrier frequency).

Algorithms for "packing" data are described in the respective standards and differ from version to version. The transfer of digital data is carried out in a similar way. The principle of Wi-Fi technology is similar to the work of mobile communications, if you do not go into technical details.

Interesting facts aboutWi-Fi You Didn't Know:

Frequency bands

Wi-Fi networks work in two frequency ranges: 2.4 GHz and 5 GHz. The first range (not a static frequency, but 13 frequencies from 2401 MHz to 2461 MHz in 5 MHz steps) differs from the second:

• signal coverage area - it covers a large area;
• speed - it is lower than at 5 GHz;
• the lowest attenuation coefficient (the signal level at 5 GHz decreases by approximately 1.5 times, depending on the circumstances, when passing obstacles in the form of walls, furniture);
• greater range of radio wave propagation;
• busier - Most devices run at 2.4GHz
• fewer channels (13 versus 17).

Standards

In 2019, the 18th 6th generation Wi-Fi specification appeared - 802.11ax. Operates on frequencies from the 5 GHz band and provides a maximum bandwidth of up to 11 Gbps. They all differ in speed, level of protection, method of signal processing, implementation of innovative functions.

IEEE standard	Frequency range, GHz	Theoretical speed (max.), Mbps
802.11 b	2,4	11
802.11 a	5	54
802.11g	2,4	108
802.11 n	2,4	300
	5	450
802.11 ac	5	670
802.11 ax	5	1100

The standards are backward compatible: the new ones are compatible with the old ones. However, older devices do not support modern specifications.

Varieties of access points

Why do we need a router? Look for the answer in the following video:

Access points that combine into a single wireless Wi-Fi network are divided into:

• autonomous - independent;
• controlled or centralized;
• non-controller.

Based on the method of controlling radio channels, the access points are divided into:

• static (channels);
• adaptive or dynamic - automatic selection of the optimal, most free channel from the range;
• multilayer.

According to the method of protection, access points are grouped into:

• public or open - unprotected, providing access to the Internet for all, often a limited number of simultaneously connected clients;
• private or private - the signal is encrypted and you need to enter a password to access the network.

On this we figured out how Wi-Fi works at the layman level. It remains to determine the pros and cons of the technology.

Advantages and disadvantages

Positive aspects of technology:

• does not require cables, which reduces the cost and speed of building networks;
• the network can include various devices: laptops, computers, smartphones and other mobile gadgets on various platforms;
• ease of network setup;
• providing the Internet for a large number of users in public places: metro, construction site, beach;
• the radiation intensity is an order of magnitude lower than that of cell phones;
• does not require a certificate to use the frequency.

Cons of wireless Wi-Fi networks:

• new standards are not compatible with old ones;
• the signal is very sensitive to obstacles;
• interference with the operation of two transmitters in the reach of each other, especially at the same frequency;
• when receiving information, devices with an access point operate sequentially;
• it is difficult to control the bandwidth of each client;
• the network operates at the speed of the slowest client;
• proven harmful effect of microwave radiation for living organisms;
• different frequency bands in countries;
• in many countries, devices with a radiation power above 100 mW require mandatory registration;
• easy hacking of all cryptographic algorithms, except for WPA3, which has not yet been released to the masses;
• no clear signal propagation area;
• when the frequency band of the channel is expanded, the wave interference is enhanced;
• with an increase in the number of clients, the overhead (delay before the operation is completed) of the response to a client's request by a router increases
• network protection is at the level of the weakest client device;
• low security level of public access points.

Nowadays, there is a Wi-Fi router in almost every home, and a wireless module is even plugged into household appliances - vacuum cleaners, refrigerators, kettles, etc. And every year the use of wireless technology is becoming wider.

Well, we are waiting for routers and network devices with support for Wi-Fi 6 to become publicly available. And we can discuss it! Write in the comments if you need help or have questions. And I say goodbye, see you on WiFiGid!

NCR Corporation / AT & T (later Lucent and Agere Systems) in Nieuwegein, The Netherlands. Products originally intended for checkout systems were marketed under the WaveLAN brand and provided data transfer rates from 1 to 2 Mbps. Vic Hayes ( Vic Hayes) - the creator of Wi-Fi - was named " father of Wi-Fi”And was on a team that helped develop standards such as IEEE 802.11b, 802.11a, and 802.11g. He left Agere Systems for Vic. Agere Systems could not compete on equal terms in difficult market conditions, despite the fact that its products occupied the niche of cheap Wi-Fi solutions. Agere's 802.11abg all-in-one chipset (codename: WARP) sold poorly and Agere Systems decided to withdraw from the Wi-Fi market in late 2004.

Principle of operation

Typically, a Wi-Fi network scheme contains at least one access point and at least one client. It is also possible to connect two clients in point-to-point mode, when the access point is not used, and the clients are connected through network adapters "directly". The access point broadcasts its network identifier (SSID) using special signaling packets at a speed of 0.1 Mbps every 100 ms. So 0.1 Mbps is the lowest data transfer rate for Wi-Fi. Knowing the SSID of the network, the client can find out if it is possible to connect to this access point. When two access points with identical SSIDs come into range, the receiver can choose between them based on the signal strength. The Wi-Fi standard gives the client complete freedom in choosing the criteria for the connection. More details on the principle of operation can be found in the official text of the standard.

Benefits of Wi-Fi

• Allows you to deploy a network without laying a cable, can reduce the cost of deploying and expanding the network. Locations where cable cannot be installed, such as outdoors and in buildings of historical value, can be served by wireless networks.
• Wi-Fi devices are widespread in the market. And devices from different manufacturers can communicate at a basic service level.
• Wi-Fi is a set of global standards. Unlike cell phones, Wi-Fi equipment can work in different countries around the world.

Disadvantages of Wi-Fi

Commercial use of Wi-Fi

Commercial access to Wi-Fi-based services is available in places such as Internet cafes, airports, and cafes around the world (commonly referred to as Wi-Fi cafes), but coverage can be considered sparse compared to cellular networks:

Wireless technologies in industry

For industrial use, Wi-Fi technologies are still offered by a limited number of suppliers. So Siemens Automation & Drives offers Wi-Fi solutions for its controllers, such as SIM cards and Wi-Fi range. Comparing Wi-Fi with other standards of cellular networks, such as CDMA, looks more correct.

However, Wi-Fi is ideal for SOHO use. The first samples of equipment appeared in the early 90s, but they entered the market only in 2005. Then the companies Zyxel, UT Starcomm, Samsung, Hitachi and many others introduced the VoIP Wi-Fi phones to the market at “reasonable” prices. In 2005 ADSL ISPs started to provide VoIP services to their customers (eg Dutch ISP XS4All). When VoIP calls became very cheap, and often free, VoIP providers were able to open up a new market for VoIP services. GSM phones with integrated support for Wi-Fi and VoIP capabilities have begun to enter the market and can potentially replace wired phones.

Direct comparisons between Wi-Fi and cellular networks are currently impractical. Wi-Fi-only phones have a very limited range, so deploying such networks is very expensive. However, deploying such networks may be the best solution for local use, such as in corporate networks. However, devices that support multiple standards can gain significant market share.

International projects

However, there is a third subcategory of networks created by communities and organizations such as universities, where free access is provided to members of the community, and those who do not belong to it are paid access. An example of such a service is the Sparknet network in Finland. Sparknet also supports OpenSparknet, a project in which people can make their own hotspots part of the Sparknet network for some benefit.

Recently, commercial Wi-Fi providers have been building free Wi-Fi hotspots and hot zones. They believe free Wi-Fi will attract new customers and return on investment.

Russian Wi-Fi Alliance

Free Wi-Fi Sticker

• October 5, 2008 The Russian Wi-Fi Alliance (Wi-Fi Alliance) was created, uniting all Wi-Fi providers providing this service free of charge. The main difference of the project is the unification of only free Wi-Fi hotspots.
• All providers and operators that are members of the Wi-Fi Alliance mark their zones with a special sticker "Free Wi-Fi is here".
• Information on access points in different cities can be found on the official website

Wi-Fi and software

• GNU / Linux: Starting with version 2.6, support for some Wi-Fi devices appeared directly in the Linux kernel. Support for Orinoco, Prism, Aironet, SourceForge.net chips. Atheros is supported through open source projects. Support for other wireless devices is available using the open source NDISwrapper driver, which allows Linux systems running on Intel-based computers Microsoft Windows for direct use. At least one commercial implementation of this idea is known. FSF has created more detailed information can be found on the Linux wireless site.

• In the operating system of the Microsoft Windows family, Wi-Fi support is provided, depending on the version, either by means of drivers, the quality of which depends on the supplier, or by means of Windows itself.
  • Earlier versions of Windows, such as Windows 2000 and earlier, do not have built-in configuration and management tools, and this depends on the hardware vendor.
  • Microsoft Windows XP supports the configuration of wireless devices. Although the initial release included rather weak support, it improved significantly with the release of Service Pack 2, and with the release of Service Pack 3, support for WPA2 was added.
  • Microsoft Windows Vista includes improved Wi-Fi support over Windows XP.
  • Microsoft Windows 7 supports all modern wireless devices and encryption protocols at the time of its release. Among other things, windows 7 creates the ability to create virtual wi-fi adapters, which allows you to connect not to one wi-fi network, but to several at once, which can be useful when using a computer in a local wi-fi network and, at the same time, in wi- fi of the network connected to the Internet.

Legal status

The legal status of Wi-Fi differs from country to country. In the United States, the 2.5 GHz band is allowed to be used without a license, provided that the power does not exceed a certain amount, and such use does not interfere with those who are licensed.

In Russia, the use of Wi-Fi without permission to use frequencies from the State Commission on Radio Frequencies (SCRF) is possible for organizing a network inside buildings, closed warehouses and industrial areas. To legally use an off-site wireless Wi-Fi network (for example, a radio channel between two neighboring houses), you must obtain permission to use frequencies. There is a simplified procedure for issuing permits for the use of radio frequencies in the 2400-2483.5 MHz band (standards 802.11b and 802.11g); to obtain such a permit, a private decision of the SCRF is not required. To use radio frequencies in other bands, in particular 5 GHz (802.11a standard), you must first obtain a private solution of the SCRF. In 2007, the situation changed with the release of the document: "Decree of July 25, 2007 N 476 On Amendments to the Decree of the Government of the Russian Federation of October 12, 2004 # 539" On the Procedure for Registration of Radioelectronic Means and High-Frequency Devices. " :, where from the list of equipment subject to registration by the sixteenth paragraph is excluded: User (terminal) radio access (wireless access) equipment in the radio frequency band 2400-2483.5 MHz with the radiation power of transmitting devices up to 100 mW inclusive. But, manipulating the implicit definition "(Since the terminal equipment can also be considered the network hub of the end backbone point), some representatives of the regional SCRF, being at the same time providers of communication services in certain regions of the Russian Federation, turn the amendments to Resolution No. 476 to their own convenience.

For violation of the procedure for the use of radio electronic means, liability is provided for under Articles 13.3 and 13.4 of the Code of Administrative Offenses of the Russian Federation (Code of Administrative Offenses of the Russian Federation). So, in July 2006, several companies in Rostov-on-Don were fined for operating open wi-Fi networks (hot spots). Most recently, the Federal Service for Supervision of Mass Communications, Communications and Cultural Heritage Protection issued a new clarification of the use and registration of all devices using Wi-Fi. Later it turned out that there is a comment by Rossvyazokhrankultura, which partially refutes the misunderstandings developed by the network media.

On the territory of Ukraine, the use of Wi-Fi without the permission of the UDCR (Ukrainian State Radio Frequency Center) is possible only if an access point with a standard omnidirectional antenna (<6 Дб, мощность сигнала ≤ 100 мВт на 2.4 ГГц и ≤ 200 мВт на 5 ГГц) для внутренних (использование внутри помещения) потребностей организации (Решение Национальной комиссии по регулированию связи Украины № 914 от 2007.09.06) В случае сигнала большей мощности либо предоставления услуг доступа в Интернет, либо к каким-либо ресурсам, необходимо регистрировать передатчик и получить лицензию УДЦР.

Turn on the search for Wi-Fi networks on your gadgets, laptops and computers - and you will see how popular wireless access technologies are, and how densely they have penetrated apartments and offices. The range of some routers is sometimes striking: when searching for networks, you can easily find a network even, for example, on the other side of the street and connect to it. And dual-band routers allow you to avoid collisions and free up the air using a higher frequency.

Typically, laptops, smartphones, TVs and gaming gadgets require an Internet connection. The operating systems Windows, Android and iOS have fundamental differences in the method of connection. Let's consider them in order

We connect a laptop and computer to our router via Wi-Fi

To connect to wifi, you need, at least, to know the password (data encryption key in case of network and traffic encryption). Consider connecting a laptop or stationary computer to an already configured and functioning router remotely.

Our goal is to connect to the internet and local network.

We check that:

• The router is connected correctly to the ISP and distributes the Internet.
• The Wi-Fi adapter is installed, functions correctly, the drivers are installed and fresh.

Connecting via WPS

The easiest, no knowledge required, way to connect to the router is through WPS... It can be hardware (using a hardware button) or software (using a pin code).

The button is pressed once and not for long (just a second press) both on the router and on the WI FI adapter.

After one or two minutes, the router and adapter themselves "negotiate" with each other about the addresses and encryption password, and the Internet becomes available on the device.

Sometimes the device may not have a WPS button, but still support it. In this case, the WPS PIN is indicated on the label: when setting up the wireless network, the OS will ask you to enter it.

Despite the apparent simplicity of the connection, it is deceiving: when activating the connection to wi-fi using WPS, three procedures are involved:

• generating a key (password);
• encrypting the generated password
• imposing additional encryption on the channel using a certificate.

Due to the incomplete transparency of this procedure - you do not know the password and connection parameters - it is recommended to use the standard connection option with the key input.

If the router was not initially configured, then by entering the WPS PIN, you can configure all the network parameters as desired: its name and key.

Standard option for connecting laptops and computers to the router

Let's take a look at how to connect to the wireless Internet through a pre-configured router.

All modern laptops are equipped with a Wi-Fi module. But a stationary computer should be equipped with a Wi-Fi adapter.

Pay attention to:

(1): All available wifi networks are visible here. Select our network (2), click (3) Connection to connect to the modem and, accordingly, the Internet.

A window appears asking you to enter a password (security key); and if the key is entered correctly, a successful Internet connection icon will appear:

Your computer can successfully use the resources of the local home network and Internet access through your router.

Connecting smartphones and gadgets to the router

For smartphones and mobile gadgets, connecting to the Internet through a router is an opportunity to save on traffic and, accordingly, money when paying for services to the operator. 4G network requires more resources and battery power than wireless access, so a smartphone will "live" longer with the Internet from a router without a GSM service provider. Any smartphone equipped with a Wi-Fi module can connect to your router's Wi-Fi.

Let's consider how to connect when the Internet is configured and distributed by an access point.

Android OS

Let's demonstrate step by step how to connect to the Internet via a router using an example of a smartphone with Android OS.

1. In the settings of your smartphone, turn on the Wi-Fi module, available networks will be automatically scanned.
2. Select your network from the list.
3. Enter the network key (which was entered at the stage of setting up the router).
4. If the connection is successful, the corresponding signature "Connected" will appear.

If you cannot connect to a network device, restart both it and your smartphone. Check the settings of your Internet distribution device and try to connect to the wireless network again as described above.

IOS OS

We will analyze step by step how to connect gadgets with the iOS operating system to the router.

In the "Settings" section, select the "Basic" section, where you can check the activation of the wireless module: when you move the slider to "ON", it automatically searches for networks available for connection. Choose your network and enter the password (network key).

If the key is correct, the iPad and iphone will successfully connect to the Internet.

Connecting to an unknown network device

Above, we discussed how to connect to a home access point, the parameters of which are known. However, there are situations that require connecting to someone else's equipment remotely, without data on the key and connection parameters.

Let's consider how to connect via Wi-Fi to a router in this case.

Password guessing

Users of home networks, due to inexperience, lack of knowledge and laziness, rarely compose complex keys. Therefore, the question of how to connect to a wireless network is not difficult to solve: there are a number of programs for selecting a key using a dictionary. For example, WiFICrack.

This program also solves the problem of how to connect to a hidden network that does not send broadcast packets. It is enough to scan the broadcast, tick the boxes of those networks, the connection to which you are interested in, download the dictionary (you can also use the built-in one) and start selection.

As a result, the file Good.txt will be created, containing the names of the networks and their keys, which were found.

Interception and cracking of a password

Programs for capturing and decrypting packets of wireless networks are also available via the Internet. The essence of the method: even in the absence of correct authentication, the network device exchanges packets with the connected gadget, which contain the key in encrypted form. Isolation of such packets and their decryption is the way to reveal the key.

This is a class of programs for advanced users with knowledge of computer security.

One example of this class of programs is Airslax.

Works with WPA / WPA2 traffic decryption and WEP encryption. The numbers indicate:

1. Scanning the air, finding all networks, their signal levels, encryption options and other features.
2. Decryption target selection. Networks are ranked in the list in ascending order of their signal strength.
3. The process of intercepting the selected network.
4. Disconnecting the client from the point to initiate a re-authentication process: the first 4 packets contain the key in encrypted form.
5. Password guessing for a captured WPA / WPA2 encrypted headshake using a dictionary.
6. Saving results.
7. Automatic WEP key guessing: a large number of DATA packets are collected and authentication is tried every 5000 collected DATA packets.
8. Here are scanned points with the possibility of authorization via WPS.
9. Using Reaver or Bully, the pin code is selected.
10. Automatic operation mode.

Security of your own network equipment

Having casually examined the main methods of standard and unauthorized connection, let us recall the basic basic requirements for your own equipment.

• Change the default usernames and their passwords on the router. Many people neglect or forget to follow this simple procedure, leaving a loophole for attackers.
• Enable encryption, which is the most difficult to decrypt - WPA2. It will significantly complicate and increase the hacking time; attackers would prefer a simpler network to connect.
• Restrict access by mac address. While it is not difficult to change the address of a network card, restricting the MAC address is a necessary procedure to protect the internal security loop.
• Change the Wi-Fi access key at least once every six months. Even if attackers do connect to your network equipment, connecting regularly and repeating the hacking procedure will force them to find a more accessible victim. This will not save you from unauthorized connections, but will significantly reduce the likelihood of hacking. Safe and fast connections for you!

(2.4 GHz and 5 GHz.)

(2.4 GHz and 5 GHz.)

Wi-Fi (pronounced as [wi-fi], short for Wireless Fidelity - a standard for broadband radio communication equipment designed for organizing local wireless networks Wireless LAN. Installation of such networks is recommended where the deployment of a cable system is impossible or economically impractical. handover function, users can move between access points across the Wi-Fi coverage area without breaking the connection Developed by the Wi-Fi Alliance consortium based on IEEE 802.11 standards.

Mobility

Mobile devices (PDAs and laptops) equipped with client Wi-Fi transmitting and receiving devices can connect to a local network and access the Internet through so-called access points or hotspots.

First Wi-fi

Wi-Fi was established in 1991 by NCR Corporation / AT&T (later Lucent and Agere Systems) in Nieuwegein, The Netherlands. Products originally intended for checkout systems were marketed under the WaveLAN brand and provided data rates from 1 to 2 Mbps. Vic Hayes, the creator of Wi-Fi, has been called the "father of Wi-Fi" and was on a team that helped develop standards such as IEEE 802.11b, 802.11a, and 802.11g. In 2003, Vic left Agere Systems. Agere Systems could not compete on equal terms in difficult market conditions, despite the fact that its products occupied the niche of cheap Wi-Fi solutions. Agere's 802.11abg all-in-one chipset (codename: WARP) sold poorly and Agere Systems decided to withdraw from the Wi-Fi market in late 2004.

Wireless-Fidelity - literally "Wireless Reliability".

Wi-Fi: How It Works
Typically, a Wi-Fi network scheme contains at least one access point (AP, from the English access point) and at least one client. The access point broadcasts its SSID (Service Set IDentifier, Network name - network identifier, network name) using special packets called signal packets, transmitted every 100 ms. Signaling packets are transmitted at 1 Mbit / s and are small in size, so they do not affect network performance. Since 1 Mbit / s is the lowest data transfer rate for Wi-Fi, a client receiving signal packets can be sure that it will be able to connect at a speed of at least 1 Mbit / s. Knowing the network parameters (i.e. SSID), the client can find out if it is possible to connect to this access point. The program built into the client's Wi-Fi card can also affect the connection. When two access points with identical SSIDs come into range, the program can choose between them based on the signal strength. The Wi-Fi standard gives the client complete freedom in choosing the criteria for connection and roaming. This is the advantage of Wi-Fi, although it means that one adapter can do this much better than the other. Recent operating systems include a feature called zero configuration that shows the user all available networks and allows them to switch between them on the fly. This means roaming will be completely controlled by the operating system. Wi-Fi transmits data over the air, so it has properties similar to a nonswitched ethernet network, and can experience the same problems as when working with nonswitched ethernet networks.

Wi-Fi and Cell Phones

Some believe that Wi-Fi and similar technologies could eventually replace cellular networks such as GSM. The obstacles to this development in the near future are the lack of roaming and authentication capabilities (see 802.1x, SIM cards and RADIUS), limited frequency range, and severely limited Wi-Fi range. It seems more correct to compare Wi-Fi with other standards of cellular networks, such as GSM, UMTS or CDMA. However, Wi-Fi is ideal for using VoIP in corporate networks or SOHO environments. The first samples of equipment were already available in the early 90s, but did not enter commercial operation until 2005. Then the companies Zyxel, UT Starcomm, Samsung, Hitachi and many others introduced the VoIP Wi-Fi phones to the market at “reasonable” prices. In 2005 ADSL ISPs started to provide VoIP services to their customers (eg German ISP XS4All). When VoIP calls became very cheap and often free, VoIP providers were able to open up a new market for VoIP services. GSM phones with integrated support for Wi-Fi and VoIP capabilities have begun to enter the market and can potentially replace wired phones. Direct comparisons between Wi-Fi and cellular networks are currently impractical. Phones that use only Wi-Fi have a very limited range, so deploying such networks is very expensive. However, deploying such networks may be the best solution for local use such as corporate networks. However, devices that support multiple standards can gain significant market share.

Commercial use of Wi-Fi

Commercial access to Wi-Fi-based services is available in places such as Internet cafes, airports, and cafes around the world (commonly referred to as Wi-Fi cafes), but coverage can be considered sparse compared to cellular networks:. Ozone and OzoneParis In France. In September 2003, Ozone began rolling out the OzoneParis network through The City of Lights. The ultimate goal is to create a centralized Wi-Fi network that completely covers Paris. The basic tenet of the Ozone Pervasive Network is that it is a nationwide network. ... WiSE Technologies provides commercial access to airports, universities, and independent cafes throughout the United States; ... T-Mobile powers Starbucks hotspots in the US and UK, as well as over 7,500 hotspots in Germany; ... Pacific Century Cyberworks provides access to Pacific Coffee stores in Hong Kong; ... The Columbia Rural Electric Association is trying to roll out 2.4 GHz Wi-Fi in a 9,500 km² area between Walla Walla and Columbia counties in Washington State and Yumatilla, Oregon; Other major networks in the US also include: Boingo, Wayport and iPass; ... Sify, an Indian Internet Service Provider, has installed 120 hotspots in Bangalore, hotels, galleries and government offices. ... Vex has a large network of hotspots located throughout Brazil. Telefonica Speedy WiFi has started to provide its services on a new growing network that has spread to the state of Sao Paulo. ... BT Openzone owns many UK hotspots based at McDonald's and has roaming agreements with T-Mobile UK and ReadyToSurf. Their clients also have access to The Cloud hotspots. ... Netstop provides access in New Zealand. ... Golden Telecom supports the city Wi-Fi network in Moscow, and also provides its own communication channels for the implementation of the Yandex.Wi-Fi () project. ... EarthLink plans to fully connect Philadelphia, USA, to the wireless Internet in the third quarter of 2007. It will be the first US metropolitan area to be fully Wi-Fi covered. The cost will be in the range of $ 20-22 per month with a connection speed of 1 Mbps. For low-income residents of Philadelphia, the cost will be $ 12-15 per month. Currently, the city center and the surrounding areas are already connected. Other areas will be connected as the transmitters are installed.

Wireless technologies in industry

For industrial use, Wi-Fi technologies are still offered by a limited number of suppliers. So Siemens Automation & Drives offers Wi-Fi solutions for its SIMATIC controllers in accordance with the IEEE 802.11b standard in the free ISM 2.4 GHz band and providing a maximum transmission rate of 11 Mbps. These technologies are mainly used for the control of moving objects and in warehouse logistics, as well as in those cases when, for any reason, it is impossible to lay wired Ethernet networks.

International projects

Another business model is to connect existing networks into new ones. The idea is that users will share their frequency range through personal wireless routers that come with special software. For example FON is a young Spanish company formed in November 2005. It intends to become the largest hotspot network in the world by the end of 2006 with 30,000 access points. Users are divided into three categories: linus, which provide free Internet access; bills selling their frequency range; and aliens using bills access. Thus, the system is similar to peer-to-peer services. While FON is receiving financial support from companies like Google and Skype, it will only be clear over time whether this idea will actually work. This service now has three main problems. The first is that more attention from the public and the media is required to move the project from the initial stage to the main stage. You should also take into account the fact that the provision of access to your Internet channel to others may be limited by your agreement with the Internet provider. Therefore, ISPs will try to protect their interests. Likewise, record companies who oppose the free distribution of MP3s are likely to do the same. And third, the FON software is still in beta testing, and it remains only to wait for the security issue to be resolved.

Free Wi-Fi

While commercial services try to leverage existing business models for Wi-Fi, many groups, communities, cities, and individuals are building free Wi-Fi networks, often using a shared peer-to-peer agreement so that networks can communicate freely with each other. Free wireless networks are usually seen as the future of the Internet. Many municipalities are teaming up with local communities to expand free Wi-Fi networks. Some groups are building their Wi-Fi networks entirely based on volunteer help and donations. For more information, see the Shared Wireless Networks section, where you can also find a list of free Wi-Fi networks located around the world (see also Free Wi-Fi hotspots in Moscow). OLSR is one of the protocols used to create free networks. Some networks use static routing, while others rely entirely on OSPF. Wireless Leiden has developed its own routing software called LVrouteD to interconnect Wi-Fi networks that are built on a fully wireless basis. Most of the networks are built on the basis of open source software, or publish their scheme under an open license. Some small countries and municipalities already provide free Wi-Fi hotspots and Wi-Fi Internet access in the community for everyone. For example, the Kingdom of Tonga or Estonia, which have a large number of free Wi-Fi hotspots throughout the country. In Paris, OzoneParis is providing free Internet access to everyone who contributes to the development of the Pervasive Network by providing the roof of their home for Wi-Fi installation. Unwire Jerusalem is a project to install free Wi-Fi hotspots in major shopping malls in Jerusalem. Many universities provide free Wi-Fi Internet access to their students, visitors, and anyone on campus. Some commercial organizations, such as Panera Bread, provide free Wi-Fi access to loyal customers. McDonald’s Corporation also provides Wi-Fi access under the McInternet brand. The service was launched at a restaurant in Oak Brook, Illinois; it is also available in many restaurants in London. However, there is a third subcategory of networks created by communities and organizations such as universities, where free access is provided to members of the community, and those who do not belong to it are paid access. An example of such a service is the Sparknet network in Finland. Sparknet also supports OpenSparknet, a project in which people can make their own hotspots part of the Sparknet network for some benefit. Recently, commercial Wi-Fi providers have been building free Wi-Fi hotspots and hot zones. They believe free Wi-Fi will attract new customers and return on investment.

Benefits of Wi-Fi

Allows you to deploy a network without laying a cable, can reduce the cost of deploying and expanding the network. Locations where cable cannot be installed, such as outdoors and in buildings of historical value, can be served by wireless networks. ... Wi-Fi devices are widespread in the market. And devices from different manufacturers can interact at the basic level of services. ... Wi-Fi networks support roaming, so the client station can move in space, moving from one access point to another. ... Wi-Fi is a set of global standards. Unlike cell phones, Wi-Fi equipment can work in different countries around the world.

Disadvantages of Wi-Fi

The frequency range and operating limits vary from country to country; in many European countries, two additional channels are allowed, which are prohibited in the USA; Japan has another channel at the top of the range, while other countries, such as Spain, prohibit the use of low frequency channels. Moreover, some countries, such as Italy, require registration of all outdoor Wi-Fi networks, or require registration of a Wi-Fi operator. ... Power consumption is quite high compared to other standards, which reduces battery life and increases device temperature. ... The most popular encryption standard, Wired Equivalent Privacy or WEP, can be hacked relatively easily even with the correct configuration (due to weak key strength). Although newer devices support the more advanced Wi-Fi Protected Access (WPA) protocol, many older access points do not support it and need to be replaced. The adoption of the 802.11i (WPA2) standard in June 2004 makes available a more secure scheme that is available in new hardware. Both schemes require a stronger password than those typically assigned by users. Many organizations use additional encryption (such as VPN) to protect against intrusion. ... Wi-Fi has a limited range. A typical 802.11b or 802.11g home Wi-Fi router has a range of 45m indoors and 90m outdoors. Distance also depends on frequency. Wi-Fi in the 2.4GHz band works farther than Wi-Fi in the 5GHz band and has a smaller range than Wi-Fi (and pre-Wi-Fi) at 900MHz. ... Overlapping signals from a closed or encrypted access point and an open access point operating on the same or adjacent channels can prevent access to an open access point. This problem can arise with a high density of hotspots, for example, in large apartment buildings, where many residents put their Wi-Fi hotspots. ... Incomplete interoperability between devices from different manufacturers or incomplete standard compliance can result in limited connectivity or slower speeds.

Wi-Fi gaming

Wi-Fi is compatible with game consoles and PDAs and allows you to play networked games over any access point. ... Iwata, President of Nintendo, announced the Wi-Fi compatible Nintendo Wii, also saying games like Super Smash Brothers will be available. The Nintendo DS game console is also Wi-Fi compatible. ... Sony PSP has one-button wireless networking support for Wi-Fi hotspots or other wireless connections.

Wi-Fi and free software

BSD OS (FreeBSD, NetBSD, OpenBSD) can work with most adapters since 1998. Drivers for Atheros, Prism, Harris / Intersil and Aironet chips (from the respective Wi-Fi device manufacturers) are usually included in BSD OS version 3. Darwin and Mac OS X, despite overlapping with FreeBSD, have their own unique implementation ... In OpenBSD 3.7, more drivers for wireless chips were included, including RealTek RTL8180L, Ralink RT25x0, Atmel AT76C50x, and Intel 2100 and 2200BG / 2225BG / 2915ABG. This partially resolved the problem of the lack of open source wireless chip drivers for OpenBSD. It is possible that some drivers implemented for other BSD systems can be ported if they have not been created yet. Ndiswrapper is also available for FreeBSD. ... Linux: Starting with version 2.6, support for some Wi-Fi devices appeared directly in the Linux kernel. Support for Orinoco, Prism, Aironet, and Atmel chips is included in the mainline kernel, ADMtek and Realtek RTL8180L chips are supported by both proprietary manufacturers and open source drivers written by the community. Intel Calexico is supported by open source drivers available from Sourceforge. Atheros and Ralink RT2x00 are supported through open source projects. Support for other wireless devices is available using the open source ndiswrapper driver, which allows Linux systems running on Intel x86 computers to wrap the manufacturer's Windows drivers for direct use. At least one commercial implementation of this idea is known. FSF has compiled a list of recommended adapters, more information can be found on the Linux wireless site.

Wireless Standards

There are currently four main Wi-Fi standards - these are 802.11a, 802.11b, 802.11g, and 802.11i. Two of them are used in Russia: 802.11b and 802.11g. In 2006, 802.11i should appear in Russia. By 2007, it is planned to start introducing another standard - 802.11n.

This is the first wireless standard that appeared in Russia and is still used everywhere. The transmission speed is rather low and the security is rather low. If desired, an attacker can take less than an hour to decrypt the network key and infiltrate your local network. For protection, the WEP protocol is used, which did not characterize itself well and was hacked several years ago. We recommend that you do not use this standard not at home, much less in corporate computer networks. An exception may be those cases when the equipment does not support another, more secure standard.

- Speed: 11 Mbps
- Radius: 50 m
- Security protocols: WEP
- Security level: low

This is a more advanced standard that replaced 802.11b. The data transfer rate has been increased by almost 5 times, and now it is 54 Mbps. When using equipment supporting superG * or True MIMO * technology, the maximum speed limit is 125 Mpbs. The level of protection has also increased: if all the necessary conditions are met with the correct settings, it can be assessed as high. This standard is compatible with the new WPA and WPA2 * encryption protocols. They provide a higher level of security than WEP. Cases of WPA2 * protocol hacking are not known yet.

* - Not supported by all hardware

- 54 Mbps, up to 125 * Mbps
- Radius: 50 m
*

This is a new standard, the implementation of which is just beginning. In this case, support for the most modern technologies, such as True MIMO and WPA2, is built directly into the standard itself. Therefore, the need for a more careful selection of equipment disappears. It is planned that this standard will replace 802.11g and nullify all hacking attempts.

- Speed: 125 Mbps
- Radius: 50 m
- Security protocols: WEP, WPA, WPA2
- Security level: High

A future standard that is currently being developed. This standard should provide long distance wireless coverage and higher speeds, up to 540 Mbps.

- Speed: 540 Mbps
- Radius: unknown m
- Security protocols: WEP, WPA, WPA2
- Security level: High

Keep in mind, however, that improper configuration of equipment that supports even the most advanced security technologies will not provide the proper level of security for your network. Each standard has additional technologies and settings to improve security. Therefore, we recommend that you only entrust the configuration of Wi-Fi equipment to professionals.

Wireless Security

Special attention should be paid to the security of wireless networks. After all, wi-fi is a wireless network and, moreover, with a long range. Accordingly, an attacker can intercept information or attack your network from a safe distance. Fortunately, there are many different ways to protect yourself today, and if configured correctly, you can be sure of the level of security you need.

An encryption protocol that uses a rather weak RC4 algorithm on a static key. There are 64-, 128-, 256- and 512-bit wep encryption. The more bits are used to store the key, the more possible key combinations, and, accordingly, the higher the network's resistance to cracking. The part of the wep key is static (40 bits in the case of 64-bit encryption), and the other part (24 bits) is dynamic (initialization vector), that is, it changes during the network operation. The main vulnerability of the wep protocol is that the initialization vectors are repeated after a certain period of time, and the cracker only needs to collect these repeats and calculate the static part of the key from them. To increase the level of security, you can use the 802.1x or VPN standard in addition to wep encryption.

Stronger encryption protocol than wep, although the same RC4 algorithm is used. A higher level of security is achieved through the use of the TKIP and MIC protocols.

- TKIP (Temporal Key Integrity Protocol). A dynamic network key protocol that changes frequently. In this case, each device is also assigned a key, which also changes.
- MIC (Message Integrity Check). Packet integrity check protocol. Protects against packet capture and redirection.

It is also possible to use 802.1x and VPN, as is the case with wep.

There are two types of WPA:

- WPA-PSK (Pre-shared key). A passphrase is used to generate network keys and to enter the network. Ideal for home or small office networks.
- WPA-802.1x. Login to the network is through the authentication server. Optimal for a large company network.

Improvement of the WPA protocol. Unlike WPA, the stronger AES encryption algorithm is used. Similar to WPA, WPA2 is also divided into two types: WPA2-PSK and WPA2-802.1x.

A security standard that includes several protocols:

- EAP (Extensible Authentication Protocol). Extended Authentication Protocol. Used in conjunction with a RADIUS server in large networks.
- TLS (Transport Layer Security). A protocol that ensures the integrity and encryption of transmitted data between the server and the client, their mutual authentication, preventing interception and spoofing of messages.
- RADIUS (Remote Authentication Dial-In User Server). Server for user authentication by login and password.

VPN (Virtual Private Network) - Virtual private network. This protocol was originally created to securely connect clients to the network over public Internet channels. The principle of VPN operation is the creation of so-called secure "tunnels" from the user to the access point or server. Although VPN was not originally created for WI-Fi, it can be used on any type of network. VPNs most often use IPSec to encrypt traffic. It provides almost one hundred percent safety. There are no known cases of VPN hacking at the moment. We recommend using this technology for corporate networks.

Additional protection methods

- Filtering by MAC address.

MAC address is a unique identifier of a device (network adapter), "hardcoded" into it by the manufacturer. On some equipment, it is possible to enable this function and allow access to the network to the necessary addresses. This will create an additional obstacle to the attacker, although not very serious - the MAC address can be changed.

- Hide SSID.

SSID is the identifier for your wireless network. Most of the equipment allows you to hide it, so your network will not be visible when scanning wi-fi networks. But again, this is not too much of a barrier if the attacker uses a more advanced network scanner than the standard Windows utility.

- Denying access to the settings of an access point or router via a wireless network.

By activating this function, you can deny access to the settings of the access point through the Wi-fi network, but this will not protect you from interception of traffic or from penetration into your network.

Keep in mind that improper configuration of equipment that supports even the most advanced security technologies will not provide the proper level of security for your network. Each standard has additional technologies and settings to improve security. Therefore, we recommend that you only entrust the configuration of Wi-Fi equipment to professionals.

The article is taken from open sources.
http://ra4a.narod.ru/Spravka5/Wi-Fi.htm