Wifi does not work in safe mode. Making your wireless network secure. Internet does not work on a computer or laptop



• Safe Mode loads a limited set of drivers to run the operating system with minimal risk of problems.
• If you need to access the local network to solve problems with the system, then you should choose Safe Mode with Networking instead of the usual Safe Mode.

After the system boots into safe mode, a window will appear confirming whether to continue working in this mode. Click Yes.



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WiFi

What affects the operation of Wi-Fi wireless networks?

What affects the operation of Wi-Fi wireless networks? What could be the source of interference and what are its possible causes? What can cause an intermittent or unstable wireless connection?

As is known, in wireless networks, radio waves (radio air) are used as a signal propagation medium, and the operation of devices and data transmission in the network occurs without the use of cable connections.
In this regard, the operation of wireless networks is affected by a greater amount of various types of interference.

1. Wi-Fi devices (access points, wireless cameras, etc.) operating within the range of your device and using the same frequency range.

The fact is that Wi-Fi devices are susceptible to even slight interference that is created by other devices operating in the same frequency range.

Wireless networks use two frequency bands - 2.4 and 5 GHz. 802.11b/g wireless networks operate in the 2.4 GHz band, 802.11a networks operate in the 5 GHz band, and 802.11n networks can operate in both the 2.4 GHz and 5 GHz bands.

The frequency range used and operating restrictions may vary from country to country.

In the 2.4 GHz frequency band, 11 or 13 channels are available for wireless networks with a width of 20 MHz (802.11b/g/n) or 40 MHz (IEE 802.11n) with 5 MHz intervals between them. A wireless device using one of the frequency channels creates significant interference on adjacent channels. For example, if an access point uses channel 6, then it strongly interferes with channels 5 and 7, and also, to a lesser extent, with channels 4 and 8. To avoid mutual interference between channels, it is necessary that their carrier frequencies are spaced apart from each other. friend at 25 MHz (5 interchannel intervals).

The figure shows the spectra of 11 channels. Color coding indicates groups of non-overlapping channels - , , , , . It is recommended to configure wireless networks located within the same coverage area on non-overlapping channels, which will experience less interference* and collisions (conflicts). Numbers of non-overlapping channels - 1, 6 and 11.
*Interference is a signal transmitted by other emitters (they may or may not be part of your Wi-Fi network) on the same channel (or close to it) that your access point is broadcasting on.
To determine the most free Wi-Fi channel, you can use the special utility InSSIDer:

Attention! In Russia, 13 wireless channels are allowed for use, three of which are non-overlapping (these are channels 1, 6 and 11).

If the wireless adapter installed on your computer/laptop/tablet/smartphone is designed for use in the US (such as Apple devices), it will only be able to use channels 1 through 11. Therefore, if you set the channel number to 12 or 13 ( and also if one of them was selected by the automatic channel selection algorithm), the wireless client (iPad/iPhone) will not see the access point. In this case, you must manually set the channel number from the range 1 to 11.

You will find additional information on how to choose the right wireless channel for your access point to ensure a reliable wireless connection in the article:

2. In some cases, it is recommended to reduce the Wi-Fi signal strength at the access point to 50 - 75%.

2.1. Using too much radiated Wi-Fi signal power does not always mean that the network will work stable and fast.
If the radio air in which your access point operates is heavily loaded (when reviewing wireless networks, you see a large number of them and their signal strength is high), then the influence of intra-channel and inter-channel interference may be felt. The presence of such interference affects network performance, because sharply increase the noise level, which leads to low communication stability due to the constant forwarding of packets. In this case, we recommend reducing the transmitter power at the access point.
If you did not find the setting for reducing the transmitter power in the access point, then this can be done in other ways: if possible, increase the distance between the access point and the adapter; unscrew the antenna on the access point (if such a feature is provided in the device); if there are removable antennas, use an antenna with a lower signal gain (for example, with a gain of 2 dBi instead of 5 dBi).

2.2. The transmitter power of the access point in the router is usually 2-3 times higher than on client mobile devices (laptop/smartphone/tablet). There may be places in the network coverage area where the client will hear the access point well, but the client’s access point will hear poorly, or not hear at all (a situation where there is a signal on the client device, but there is no connection). In the communication channel, asymmetry arises from different values ​​of power and sensitivity of the receivers.
To ensure a good signal level, it is necessary that the connection between the client device and the access point be as symmetrical as possible so that the access point and the client can confidently hear each other.
As strange as it may seem, in order to eliminate asymmetry and obtain a more stable connection, sometimes it is necessary to reduce the transmitter power at the access point.

3. Bluetooth devices, wireless keyboards and mice that work within the coverage area of ​​your Wi-Fi device.

Bluetooth devices and wireless keyboards and mice operate in the 2.4 GHz frequency range, and therefore may affect the operation of the access point and other Wi-Fi devices.

4. Long distances between Wi-Fi devices.

Please remember that Wi-Fi wireless devices have a limited range. For example, a home Internet center with an 802.11b/g Wi-Fi access point has a range of up to 60 m indoors and up to 400 m outdoors.
Indoors, the range of a wireless access point can be limited to several tens of meters - depending on the configuration of the rooms, the presence of solid walls and their number, as well as other obstacles.

5. Obstacles.

Various obstacles (walls, ceilings, furniture, metal doors, etc.) located between Wi-Fi devices can partially or significantly reflect/absorb radio signals, which leads to partial or complete loss of the signal.
In cities with multi-storey buildings, the main obstacle to the radio signal is buildings. The presence of permanent walls (concrete + reinforcement), sheet metal, plaster on the walls, steel frames, etc. affects the quality of the radio signal and can significantly degrade the performance of Wi-Fi devices.
Indoors, mirrors and tinted windows can also cause radio signal interference. Even the human body attenuates the signal by about 3 dB.

Below is a table showing the loss of efficiency of a Wi-Fi signal when passing through various environments. The data is given for a network operating in the 2.4 GHz frequency range.

* Effective distance- means how much the range of action will decrease after passing the corresponding obstacle compared to open space. For example, if in an open space the Wi-Fi range is up to 400 meters, then after passing through one interior wall it will decrease to 400 m * 15% = 60 meters. After the second again 60 m * 15% = 9 meters. And after the third 9 m * 15% = 1.35 meters. Thus, it is most likely impossible to establish a wireless connection through three interior walls.

Outdoors, the quality of the transmitted signal can be affected by the terrain (for example, trees, forests, hills).
Atmospheric interference (rain, thunderstorm, snowfall) can also cause a decrease in wireless network performance (if the radio signal is transmitted outdoors).

6. Various household appliances operating within the coverage area of ​​your Wi-Fi device.

We list household appliances that may cause deterioration in the quality of Wi-Fi communications:

• Microwave ovens. These devices may weaken the Wi-Fi signal because... usually also operate in the 2.4 GHz band.
• Baby monitors. These devices operate in the 2.4 GHz band and produce interference, resulting in poor Wi-Fi connection quality.
• CRT monitors, electric motors, wireless speakers, cordless phones and other wireless devices.
• External sources of electrical voltage, such as power lines and power substations, can be sources of interference.

7. Devices using the USB 3.0 standard may interfere with Wi-Fi networks in the 2.4 GHz band.

When testing Internet centers in our laboratory, we did not encounter a situation where a connected device via USB 3.0 would affect the operation of the wireless network in the 2.4 GHz range. But we cannot exclude such cases.

This problem may be caused by interference coming from connected devices or cables, connectors, connectors with a USB 3.0 interface. In particular, there may be missing or insufficient shielding on the cable or connector of the connected device, which may result in interference at frequencies in the 2.4 GHz band (which is the frequency at which most wireless devices operate).

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How to scan a Wi-Fi network and determine the most free channel?

How to determine the most free Wi-Fi channel for a wireless adapter or access point?

As a rule, the optimal channel number is selected automatically based on periodic analysis of the radio broadcast. Typically, this is a radio channel that is as far away as possible from neighboring wireless networks, if there are any within the range of your access point, in order to avoid frequency conflict, which can lead to problems when using a wireless network.

Judging by the fact that you came across this article on the Internet, you know about the security problems of Wi-Fi networks and the need for its proper configuration. But it’s unlikely that an untrained person will be able to figure it out and set it up correctly right away. And many users generally think that everything on the router “out of the box” is already configured with the maximum level of security. In most cases, this is a mistaken opinion. Therefore, now I will give the basic rules for setting up the security of WiFi networks using the example of a TP-Link router.

1. Be sure to enable network encryption.
Never leave your network open. If your home WiFi is not encrypted, this is not correct. Anyone can connect to you and use your Internet access for their own purposes.

2. If possible, use only WPA2-PSK encryption type

If your router settings use WEP encryption, be sure to change it to WPA2, because WEP (Wired Equivalent Privacy) is outdated and has serious vulnerabilities. And WPA2 is the strongest in use right now. WPA should only be used if you have devices that cannot work with WPA2.

If you do not use the WPS function, be sure to disable it. In some router models, this is a serious vulnerability due to the standard configuration. As practice shows, in 90% of cases WPS is not used at all.

4. Change the default SSID network name.

Very often, a wireless router model is used as the SSID (Service Set Identifier), which makes it easier for an attacker to hack Wi-Fi. Therefore, you definitely need to change it to any other one. The name can be any word in Latin and numbers. Don't use Cyrillic.

5. Change the router's default password.

An example is GPON ONT terminals from ZTE. Due to the fact that they all used the same password by default, which no one changed when setting up the device. Because of this, many home networks in Moscow and St. Petersburg were hacked. Accordingly, an attacker could gain access to the router settings, Internet channel and home network.

6. Enable the router's firewall.

Almost all routers are equipped with a built-in firewall (aka firewall), which can be disabled by default. Make sure it's turned on. For even greater security, you should make sure that every computer on your network is also running firewall and antivirus software.

7. Enable filtering of MAC addresses of Wi-Fi clients.

Every computer, laptop, or mobile device has a unique identifier on the network called a MAC address. This allows the WiFi router to keep track of all devices connected to it. Many WiFi routers allow administrators to physically enter the MAC addresses of devices that can connect to the network.

This way, only those devices that are in the table will be able to connect to your home network. Others won't be able to do it at all, even if they guess the password.

8. Disable remote administration.
Most routers allow administrators to connect remotely from the Internet to the device's web interface or command line. If you don't need it, disable this feature. The device settings will still be available from the local network.

So, by taking a few minutes to make sure our home WiFi network is set up at the optimal level of security, you can avoid problems and prevent them from happening in the future.

If your computer is infected with viruses, it is useful to know information on how to turn on the Internet in safe mode. With this method of starting the operating system, only minimal components will load. The main advantage is that applications that are registered in startup will not load.

The login process is straightforward. It may only differ depending on the version of WINDOWS you are using.

There are three types:

• The standard option, in which only the programs and services necessary for the operation of the operating system are launched. With this method, network drivers will not start, so logging onto the Internet will not be possible.
• The second method involves launching network drivers. Unlike the first option, the user gets the opportunity to access the network.
• Login using the command line. The peculiarity of this method is that after launching the standard option, the command line appears.

To connect to safe mode in Windows, you need to perform a number of actions:

1. You need to remove all disks and floppy disks from the computer, then restart. You need to activate the “Start” button and select the “Restart” option.
2. If the user has one operating system installed on the computer, then during the reboot process you need to hold down the F8 button. You need to press it until the Windows inscription appears. If the logo appeared before pressing the button, you need to repeat the steps again. To do this, you need to boot completely and then restart again.
3. If several operating systems are installed, you need to use the arrows to select the one you need. Then the F8 button is pressed.

The user will see a panel of additional download options. Use the arrow keys to select the option you want and press enter.

The method of connecting will depend on the type of operating system. For example, if we are talking about seven, then there are two ways. The first option involves logging in while the program is starting, the second during operation. In the first case, the mode will work even in the event of serious failures on the computer.

To enter safe mode on Windows 7, you need to do the following:

1. Restart your computer if it was turned on.
2. Before starting, you need to press F8 several times. It is best to do this at least three times.
3. A window will appear asking you to select additional options for downloading.
4. Having selected safe mode, you need to press the “enter” key.

Important! Often on laptops you have to press F8 along with the Fn key.

Purpose

Every Windows operating system has this boot method. It’s impossible to just go into it. If the operating system is working correctly, then it is not visible. It is considered one of the diagnostic methods.

Once Windows is started in this way, the user will see a typical system, but it will have simplified graphics and a desktop background. The main feature is that in this version only basic programs for Windows will work. All services that are configured to autostart at startup will be disabled.

Many users wonder why turn on in safe mode if many services will not function. This method is necessary if you cannot connect Windows at all. The reasons for this can be various, such as a virus or operational errors. If the operating system does not start due to some system error, then logging in using the security method may also not always work.

This type of run often helps identify the problem. For example, if an incompatible driver was installed. In such a situation, you can find the reason why the operating system does not start in the standard manner.

If you turn it on in a safe way, you can run an antivirus program. It will help clean your computer. After this, you can start the system for recovery.

Possible operations

If you use this method, a number of operations become available to the user:

• Ability to check the operating system for viruses. Programs that are installed on autorun will not start. Namely, they are where viruses are most often located.
• Configure and restore the system. This is best done when connecting.
• Update and install new drivers. With this mode, only the most minimally necessary ones will be loaded. If the computer is not working well, and the problem lies in the drivers, this method can solve the problem.

The user will also be able to check the operation of the computer. If it's a software issue, it will function well with this input. If the problems persist, then there is a breakdown in the hardware system.

Is it possible to use the Internet

Often users are faced with the situation that the Internet does not work in safe mode. If you cannot access it, it means that blocking programs are installed on your computer. In such a situation, it is recommended to restart the computer and turn on the usual method. To do this, in the “system configuration” tab, select “normal startup”, then “general”.

Then you need to clean your computer from malicious and blocking programs. It is also recommended to reinstall your antivirus program.

Reasons for lack of connection

If you enable safe mode, most often you still cannot access the Internet. This happens if the network drivers have not been activated. This situation occurs with the standard boot type. To be able to access the Internet, you need to choose the second method with connecting drivers.

Programmers do not advise doing this, as there is a possibility of aggravating the breakdown situation. This is because this boot method disables many systems on the computer.

By starting the operating system with the exclusion of unnecessary programs, safe mode is one of the important types of diagnosing the state of the computer. It helps restore the computer's functionality after breakdowns and malfunctions occur.

Password and MAC address filtering should protect you from hacking. In fact, safety largely depends on your caution. Inappropriate security methods, uncomplicated passwords, and a careless attitude toward strangers on your home network provide attackers with additional attack opportunities. In this article, you will learn how to crack a WEP password, why you should abandon filters, and how to secure your wireless network from all sides.

Protection from uninvited guests

Your network is not secure, therefore, sooner or later, an outsider will connect to your wireless network - perhaps not even on purpose, since smartphones and tablets can automatically connect to unsecured networks. If he just opens several sites, then, most likely, nothing bad will happen except for the consumption of traffic. The situation will become more complicated if a guest starts downloading illegal content through your Internet connection.

If you have not yet taken any security measures, then go to the router interface through a browser and change your network access data. The router address usually looks like: http://192.168.1.1. If this is not the case, then you can find out the IP address of your network device through the command line. In the Windows 7 operating system, click on the “Start” button and enter the “cmd” command in the search bar. Call up the network settings with the “ipconfig” command and find the “Default gateway” line. The specified IP is the address of your router, which must be entered in the address bar of the browser. The location of your router's security settings varies by manufacturer. As a rule, they are located in a section with the name “WLAN | Safety".

If your wireless network uses an unsecured connection, you should be especially careful with content that is located in shared folders, since if it is not protected, it will be available to other users. At the same time, in the Windows XP Home operating system, the situation with shared access is simply catastrophic: by default, passwords cannot be set here at all - this function is present only in the professional version. Instead, all network requests are made through an unsecured guest account. You can secure your network in Windows XP using a small manipulation: launch the command line, enter “net user guest YourNewPassword” and confirm the operation by pressing the “Enter” key. After restarting Windows, you will be able to access network resources only if you have a password; however, finer tuning in this version of the OS, unfortunately, is not possible. Managing sharing settings is much more convenient in Windows 7. Here, to limit the number of users, just go to the “Network and Sharing Center” in the Control Panel and create a password-protected home group.

The lack of proper protection in a wireless network is a source of other dangers, since hackers can use special programs (sniffers) to identify all unprotected connections. This way, it will be easy for hackers to intercept your identification data from various services.

Hackers

As before, the two most popular security methods today are MAC address filtering and hiding the SSID (network name): these security measures will not keep you safe. In order to identify the network name, an attacker only needs a WLAN adapter, which switches to monitoring mode using a modified driver, and a sniffer - for example, Kismet. The attacker monitors the network until a user (client) connects to it. It then manipulates the data packets and thereby kicks the client off the network. When the user reconnects, the attacker sees the network name. It seems complicated, but in fact the whole process only takes a few minutes. Bypassing the MAC filter is also easy: the attacker determines the MAC address and assigns it to his device. Thus, the connection of an outsider remains unnoticed by the network owner.

If your device only supports WEP encryption, take immediate action - such a password can be cracked even by non-professionals in a few minutes.

Particularly popular among cyber fraudsters is the Aircrack-ng software package, which, in addition to the sniffer, includes an application for downloading and modifying WLAN adapter drivers, and also allows you to recover the WEP key. Well-known hacking methods are PTW and FMS/KoreK attacks, in which traffic is intercepted and a WEP key is calculated based on its analysis. In this situation, you have only two options: first, you should look for the latest firmware for your device, which will support the latest encryption methods. If the manufacturer does not provide updates, it is better to refuse to use such a device, because in doing so you are jeopardizing the security of your home network.

The popular advice to reduce Wi-Fi range only gives the appearance of protection. Neighbors will still be able to connect to your network, but attackers often use Wi-Fi adapters with a longer range.

Public hotspots

Places with free Wi-Fi attract cyber fraudsters because huge amounts of information pass through them, and anyone can use hacking tools. Public hotspots can be found in cafes, hotels and other public places. But other users of the same networks can intercept your data and, for example, take control of your accounts on various web services.

Cookie Protection. Some attack methods are truly so simple that anyone can use them. The Firesheep extension for the Firefox browser automatically reads and lists the accounts of other users, including Amazon, Google, Facebook and Twitter. If a hacker clicks on one of the entries in the list, he will immediately have full access to the account and will be able to change the user's data at his discretion. Firesheep does not crack passwords, but only copies active, unencrypted cookies. To protect yourself from such interceptions, you should use the special HTTPS Everywhere add-on for Firefox. This extension forces online services to always use an encrypted connection via HTTPS if supported by the service provider's server.

Android protection. In the recent past, widespread attention has been drawn to a flaw in the Android operating system that could allow scammers to gain access to your accounts in services such as Picasa and Google Calendar, as well as read your contacts. Google fixed this vulnerability in Android 2.3.4, but most devices previously purchased by users have older versions of the system installed. To protect them, you can use the SyncGuard application.

WPA 2

The best protection is provided by WPA2 technology, which has been used by computer equipment manufacturers since 2004. Most devices support this type of encryption. But, like other technologies, WPA2 also has its weak point: using a dictionary attack or the bruteforce method, hackers can crack passwords - however, only if they are unreliable. Dictionaries simply go through the keys stored in their databases - as a rule, all possible combinations of numbers and names. Passwords like “1234” or “Ivanov” are guessed so quickly that the hacker’s computer doesn’t even have time to warm up.

The bruteforce method does not involve using a ready-made database, but, on the contrary, selecting a password by listing all possible combinations of characters. In this way, an attacker can calculate any key - the only question is how long it will take him. NASA, in its security guidelines, recommends a password of at least eight characters, and preferably sixteen. First of all, it is important that it consists of lowercase and uppercase letters, numbers and special characters. It would take a hacker decades to crack such a password.

Your network is not yet fully protected, since all users within it have access to your router and can make changes to its settings. Some devices provide additional security features that you should also take advantage of.

First of all, disable the ability to manipulate the router via Wi-Fi. Unfortunately, this feature is only available on certain devices, such as Linksys routers. All modern router models also have the ability to set a password for the management interface, which allows you to restrict access to settings.

Like any program, the router firmware is imperfect - small flaws or critical holes in the security system are not excluded. Usually information about this instantly spreads across the Internet. Check regularly for new firmware for your router (some models even have an automatic update feature). Another advantage of flashing firmware is that it can add new functions to the device.

Periodic analysis of network traffic helps to recognize the presence of uninvited guests. In the router management interface you can find information about which devices connected to your network and when. It is more difficult to find out how much data a particular user has downloaded.

Guest access - a means of protecting your home network

If you protect your router with a strong password using WPA2 encryption, you will no longer be in any danger. But only until you share your password with other users. Friends and acquaintances who, with their smartphones, tablets or laptops, want to access the Internet through your connection are a risk factor. For example, the possibility that their devices are infected with malware cannot be ruled out. However, you won't have to refuse your friends because of this, since top-end router models, such as the Belkin N or Netgear WNDR3700, provide guest access specifically for such cases. The advantage of this mode is that the router creates a separate network with its own password, and the home one is not used.

Security Key Reliability

WEP (WIRED EQUIVALENT PRIVACY). Uses a pseudo-random number generator (RC4 algorithm) to obtain the key, as well as initialization vectors. Since the latter component is not encrypted, it is possible for third parties to intervene and recreate the WEP key.

WPA (WI-FI PROTECTED ACCESS) Based on the WEP mechanism, but offers a dynamic key for enhanced security. Keys generated using the TKIP algorithm can be cracked using the Bek-Tevs or Ohigashi-Moriya attack. To do this, individual packets are decrypted, manipulated, and sent back to the network.

WPA2 (WI-FI PROTECTED ACCESS 2) Uses the reliable AES (Advanced Encryption Standard) algorithm for encryption. Along with TKIP, the CCMP protocol (Counter-Mode/CBC-MAC Protocol) has been added, which is also based on the AES algorithm. Until now, a network protected by this technology could not be hacked. The only option for hackers is a dictionary attack or “brute force method”, when the key is guessed by guessing, but with a complex password it is impossible to guess it.