It's understandable that a situation where the router's lights are green, smartphones and tablets connect to the network via Wi-Fi without any issues, but a desktop computer or laptop connected via LAN cable shows no connection at all is a source of confusion. Users often mistakenly assume that if the wireless network is functioning, then so is the provider. Rostelecom It has nothing to do with it, and the problem lies solely in the PC's operating system settings. However, a physical twisted-pair connection and a radio channel are fundamentally different interfaces, each with its own vulnerabilities and specific configuration requirements.
In this article we will take a detailed look at the technical reasons why local area network The connection can be lost while Wi-Fi is active, and we'll provide a step-by-step procedure for restoring access. We'll cover hardware compatibility, TCP/IP stack settings, and specific authorization parameters used by your provider. Understanding the differences between the physical connection layer and the logical protocol settings will help you quickly isolate the problem without calling a technician.
Before attempting complex repairs, it's important to rule out basic physical defects that often go unnoticed. An Ethernet cable may appear intact but have an internal broken wire, while a computer's network card may be disabled by software or operating in an incorrect power-saving mode. Unlike Wi-Fi, where the router itself assigns connection parameters, a wired connection often requires strict adherence to static settings or the correct operation of the DHCP server. Let's go through all the diagnostic stages in sequence.
Primary diagnostics of the physical layer and indicators
Begin your analysis with a visual inspection of the ports and cables. On the back of the router and system unit (or laptop), there are RJ-45 connectors with LED indicators next to them. If the physical connection is correct and the cable is working properly, one of the indicators should be solid (usually green or orange), indicating a link, and the other should blink, indicating data transfer activity. If the indicators don't light at all, this indicates a physical break in the circuit.
Often, the problem lies in the patch cord itself. Cables laid along the floor or behind furniture are subject to mechanical stress, twisting, and kinking. Even if the outer insulation is intact, the copper wires inside may be damaged. Try replacing the existing cable with a known-good one, such as the one that came with your router, by connecting it directly between your computer and the LAN port.
It's also worth paying attention to the condition of the port itself. Dust, oxidation of the contacts, or mechanical damage to the "tongue" inside the connector can cause unstable contact. Try moving the cable to another available port. LAN on the router. Some models Rostelecom (eg Sagemcom or Sercomm) allow you to disable individual ports in the web interface, so changing the socket can bypass the software block.
If replacing the cable and port doesn't help, and the indicators remain silent, the problem may lie with the computer's network card drivers or hardware failure. In Windows Device Manager, check whether the network adapter is detected and whether it has an exclamation mark. If the device is not listed, it may be faulty or disabled in the BIOS.
IP address conflict and TCP/IP protocol settings
One of the most common reasons why the internet works over the air but not over the wire is an addressing conflict or a problem in the TCP/IP protocol stack. The router, acting as a DHCP server, automatically assigns addresses to all connected devices. However, the computer may retain old, outdated settings or attempt to use a static IP address that is inappropriate for the current subnet.
To check the current settings, open the command prompt. Click Win + R, enter cmd and press Enter. In the black window, enter the command ipconfig /allFind the section that corresponds to your Ethernet adapter. If in the "IP Address" field you see a value starting with 169.254.x.x, this means that the computer was unable to obtain an address from the router. Rostelecom and switched to self-assignment mode. In this case, there will be no network access.
To fix this, you need to reset your network settings and renew your address lease. In the command line, run the following commands one by one, pressing Enter after each:
ipconfig /releaseipconfig /renew
ipconfig /flushdns
netsh int ip reset
netsh winsock reset
After running the last command, be sure to reboot your computer. This will flush the DNS cache, reset the socket API, and reinstall the TCP/IP stack. This often resolves issues where the system is stuck in an incorrect network state.
If the problem persists, check your adapter settings manually. Go to Control Panel → Network and Internet → Network and Sharing Center → Change adapter settingsFind "Local Area Connection" or "Ethernet," right-click, and select "Properties." Find "Internet Protocol Version 4 (TCP/IPv4)" in the list, select it, and click "Properties." Make sure "Obtain an IP address automatically" and "Obtain DNS server address automatically" are checked.
Problems with network card drivers and settings
The software that controls your network adapter may not function properly, especially after Windows updates or installing a new antivirus. The driver may be corrupted, outdated, or, conversely, too new and contain compatibility errors with your specific router model. Rostelecom.
Open Device Manager (right-click Start and select Device Manager). Expand the Network Adapters branch. Find your Ethernet controller (usually listed as Realtek, Intel, or Qualcomm Atheros). Right-click and select Uninstall device. In the window that appears, check the box next to "Delete the driver software for this device," if present, and confirm. Then, select Action → Scan for hardware changes from the menu. The system will redetect the card and install the driver.
It's also worth checking your power management settings. Windows often tries to save power by disabling the network card, which can cause connection drops. In Device Manager, under your adapter's properties, go to the Power Management tab and uncheck "Allow the computer to turn off this device to save power."
⚠️ Attention: When uninstalling drivers, make sure you have internet access via Wi-Fi or another connection so that Windows can automatically download the latest software. If you only have internet access via a cable, download the driver from the motherboard or laptop manufacturer's website on another device beforehand.
In some cases, manually setting the duplex speed can help. In the adapter properties, click the "Configure" button, go to the "Advanced" tab, and find the "Speed & Duplex" setting. By default, it's set to "Auto Negotiation." Try forcing it. 100 Mbps Full DuplexSometimes automatic configuration fails to match the speed to the router port, and fixing the value solves the problem.
Rostelecom router settings: MAC filtering and binding
If all the settings on your computer are correct, the problem may lie in the router's configuration. Providers, including RostelecomMAC address binding is often used for subscriber authentication. When you connect a new device (your PC) via cable, the router may block its access if the MAC address isn't on the allowed list or if it's "stuck" on an old device.
Log in to the router's web interface. To do this, enter the address in your browser. 192.168.1.1 or 192.168.0.1 (The exact address is indicated on the sticker on the bottom of the device). The login and password are also located there (often admin/admin or admin/1234). You need to find the section related to WAN or Internet connection.
Check your connection type. Rostelecom the protocol is often used PPPoEIf the settings are incorrect, the router may not distribute internet to the wired ports, although Wi-Fi (which may operate at the bridged level or have its own priorities) will still function. Make sure the connection status is "Connected." If the status is "Disconnected" or "Connecting," a reconnection or a router firmware update may be required.
How to clone a MAC address?
If your ISP has bound your internet connection to the MAC address of your old router or computer, find the "Network" -> "MAC Clone" section in your router settings. Click the "Clone MAC Address" button to make your current PC or router appear to your ISP under the correct identifier.
Also check the "Security" or "MAC Filtering" sections. Make sure there's no blocking of new devices connecting via LAN ports. Sometimes users accidentally enable parental controls or guest mode, which restricts WAN access for wired clients.
The impact of antiviruses and firewalls
Third-party antivirus suites (Kaspersky, ESET, Avast, etc.) have built-in firewalls that can block incoming and outgoing connections, classifying your home network as "Public." In this mode, many ports and services are blocked for security purposes, which can appear to completely disable internet access.
Try temporarily disabling your antivirus and Windows Firewall. If you can connect to the internet via cable after this, the issue lies with your filtering rules. You'll need to find the network profile in your antivirus settings and change it from "Public" to "Home" or "Trusted," and reset your firewall settings to default.
The built-in Windows Firewall could also be the culprit. Go to Control Panel → Windows Defender Firewall and click Restore Defaults. This will reset all rules to factory settings, which often resolves conflicts caused by system crashes.
| Symptom | Possible cause | Solution method |
|---|---|---|
| The LAN indicator is not lit. | Cable break, port malfunction | Replacing the patch cord, checking the ports |
| IP address 169.254.xx | DHCP failure, address conflict | Reset TCP/IP with the ipconfig /renew command |
| There is a local network, but no internet. | Incorrect DNS, blocked by ISP | Register DNS 8.8.8.8, PPPoE check |
| Unstable connection | Drivers, power supply | Update drivers, disable power saving |
Resetting network and router settings
If none of the software methods help, there's a radical but effective step left: a complete reset. Start with the Windows network stack. Windows 10 and 11 have a built-in network reset feature. Go to Settings → Network & Internet → Advanced network settings → Network reset. Click the "Reset now" button. The computer will restart, and all network components will be reinstalled.
If this doesn't help, it's possible the router itself has accumulated software junk or a configuration error has occurred that's difficult to trace manually. In this case, resetting the router will help. Rostelecom to factory settings. There is a small hole with the inscription on the device body Reset or DefaultPress it with a paper clip for 10-15 seconds until the indicators flash simultaneously.
⚠️ Attention: After resetting your router, your internet will stop working completely because your PPPoE settings (username and password) will be lost. You'll need to reconfigure the router using the quick setup wizard or call your ISP specialist for configuration. Make sure you have a valid internet connection with your username and password.
☑️ Wired Connection Diagnostic Checklist
Resetting the router and reconfiguring it will usually resolve any software conflicts that were interfering with the wired interface. In most cases (about 90%), replacing the cable or resetting Windows network settings resolves the issue.
Frequently Asked Questions (FAQ)
Why is the yellow light on the LAN port instead of green?
A yellow (orange) indicator usually indicates a connection, but the speed is limited to 100 Mbps instead of 1 Gbps. This can be due to cable quality (using only 4 wires instead of 8) or router settings. The internet should still work, but at a slower rate.
Can a virus block the Internet only on a cable?
Theoretically, yes, some malware can change the settings of a specific network adapter or set static routes that block traffic. However, most often, viruses affect all interfaces at once. Scan your system with an antivirus scanner, such as Dr.Web CureIt!.
Should I reinstall Windows if nothing helps?
Reinstalling the OS is a last resort. Before doing so, try booting from a Live USB (for example, Linux) and checking your internet connection. If everything works there, the problem is definitely with the drivers or Windows. If not, the problem is hardware (card, cable, router).
Does cable length affect speed and stability?
Yes, the standard length of twisted pair cable without signal amplifiers should not exceed 100 meters. However, problems can begin after 50-70 meters, especially if the cable is of low quality (CCA - copper-clad aluminum). For long runs, use only pure copper cable (OFC).