Setting up an internal computer network (LAN) is a fundamental task for anyone who wants to share files between devices, play online, or use shared resources like printers and NAS storage. Many users mistakenly believe that a home network requires a WAN connection to function, but this is not the case. Local area network It operates independently of external communication channels, relying solely on the capabilities of the router and network adapters of your devices. In this case, the router acts not as a gateway to the internet, but as a central switch and IP address distributor.
Lack of access to the ISP or temporary problems with the WAN cable are not obstacles to the full operation of the network indoors. On the contrary, this configuration often improves data security, as devices are completely isolated from external threats and attacks from the global network. All you need is a functioning router and devices with Wi-Fi or Ethernet ports to deploy a fully functional data exchange infrastructure.
In this article, we'll cover the process of setting up hardware, configuring TCP/IP, and setting up shared access in operating systems in detail. You'll learn how to correctly assign static addresses, configure your router's DHCP server to distribute addresses, and ensure computers can see each other. TP-Link, ASUS, Mikrotik and other brands have similar logic for operating in local network mode, which makes this instruction universal.
How a router works without connecting to a provider
When you disconnect the ISP cable from the port WAN/Internet If you simply don't configure a connection to it, the router ceases to function as a gateway to the outside world. However, its internal functions remain fully active. The device's primary tasks in this mode are switching traffic between LAN ports and wireless clients, as well as addressing devices within the perimeter. Router continues to manage data flows, directing packets from one connected device to another based on MAC addresses and IP tables.
The key element here is the DHCP server. Even without internet access, the router should automatically assign IP addresses to connected devices so they can "see" each other. If this service is disabled, you'll have to manually assign IP addresses to each computer, which is inconvenient and error-prone. The internal network is built on a protocol. TCP/IP, and for it to function it is enough that all devices are on the same subnet.
It's important to understand that the lack of internet access doesn't affect the speed of data transfer within the network. The speed is limited only by the capabilities of your Wi-Fi standard (e.g., 802.11ac or ax) and Ethernet port speeds (100 Mbps or 1 Gbps). This means that copying movies or installing games over the local network will occur at the maximum possible hardware speed.
⚠️ Note: Some router models may have an "Internet" indicator that lights red or flashes when there is no connection to the ISP. This is normal behavior and does not indicate a problem with the local network. Ignore this indicator if you only need internal connectivity.
It's also worth noting that in offline mode, the router won't attempt to synchronize time via NTP servers or update firmware, which can save some CPU resources. However, for some network protocols (such as Kerberos for domains) to function correctly, the time on devices must be synchronized manually or via a local time server.
Physical connection and entering settings
The first step is to properly physically connect the devices. It's best to connect the computer you'll be using to the router via an Ethernet cable to any LAN port. This will prevent connection loss when changing Wi-Fi settings. If you plan to use a wireless connection only, make sure you know the factory network name (SSID) and password indicated on the sticker on the bottom of the device.
After connecting the cable, check your computer's network settings. Your Windows or macOS operating system should be set to obtain an IP address automatically. This is usually the default setting. DHCP, but if static addresses were previously used, they need to be reset. The computer should receive an address in the range assigned by the router by default (often 192.168.0.x or 192.168.1.x).
To access the web interface, open your browser and enter the router's IP address in the address bar. Standard addresses usually look like this: 192.168.0.1, 192.168.1.1 or 192.168.31.1If your browser says the site is unavailable or the connection is not secure, that's normal—just ignore the security warning and go to the page. Enter your username and password (the default is often admin/admin).
☑️ Preparing for setup
Configuring DHCP and LAN settings
After successfully logging into the control panel, you need to make sure the DHCP server is running. Find the section usually called LAN, Local Network or DHCP Server. Here you will see the subnet settings. Make sure the DHCP function is enabled (Enable). It is this server that will distribute addresses to all devices connecting to your isolated network.
Pay attention to the address pool. It should be wide enough to cover all your devices, but not extend beyond the subnet. For example, if the router's IP address 192.168.1.1, then the subnet mask should be 255.255.255.0, and the address pool can start with 192.168.1.100 and end in 192.168.1.200. The address range must be strictly within the same subnet, otherwise the devices will not be able to exchange data.
If you plan to use static IP addresses for servers or printers, make sure they are outside the automatic distribution range or reserved via the Address ReservationThis will prevent address conflicts when the router accidentally assigns a occupied address to a new device. Save the settings, after which the router may prompt you to reboot.
In some advanced router models (for example, Mikrotik or Keenetic) You can completely disable NAT and the firewall for local interfaces, but for a basic home network, the standard DHCP settings are sufficient. The main thing is that all devices receive an address, mask, and gateway automatically.
Wireless network (Wi-Fi) configuration
Go to the wireless settings section, which may be called Wireless, Wi-Fi or Wireless networkHere you need to specify the network name (SSID). Come up with a unique name to avoid confusing your local network with your neighbors' if they suddenly appear. Since there's no internet connection, connection security is ensured only by encrypting traffic within the perimeter.
Be sure to set a strong encryption method. Select a standard WPA2-PSK or WPA3, if your devices support it. Using legacy WEP or open network (Open) is not recommended, as it allows anyone within range to connect to your shared folders. The password should be complex, even if the network is not connected to the internet.
Also check your frequency settings. If your router is dual-band, you can create two networks: 2.4 GHz and 5 GHz. For transferring large files over a local network (such as 4K video), the 2.4 GHz band is preferable. 5 GHz, as it offers higher speeds and is less susceptible to interference from microwaves and Bluetooth devices. Make sure that AP Isolation is enabled on both bands—it should be TURNED OFF, otherwise the devices will not see each other.
⚠️ Important: The Client Isolation (AP Isolation) feature prevents devices connected to Wi-Fi from communicating with each other. To create a local network, this feature must be disabled in the wireless settings.
Setting up sharing in Windows
Once the router is configured and distributing addresses, you need to configure the operating system. In Windows, go to Control Panel → Network and Sharing Center. Select Change advanced sharing settings. In the Private profile (or Current profile), enable the option Network discovery And File and Printer Sharing.
It's important to disable password protection if you don't want to enter your Windows account login and password every time you connect from another device. At the bottom of the settings page, find "All Networks" and select "Turn off password-protected sharing." This will make it easier to connect smartphones, TVs, and other devices that don't support Windows logins.
Next, select the folder you want to share. Right-click, select "Properties" → "Sharing" tab → "Advanced." Check "Share" and set the permissions (usually "Read" for everyone or "Full Control" for trusted users). The network folder path will look like this: \\ComputerName\FolderName or \\192.168.1.XX\FolderName.
Problems with computer visibility
If the computers can't see each other, check the Function Discovery Resource Publishing service in Windows. It should be running. Also, make sure the network type is set to "Private" and not "Public." Windows blocks discovery by default in the public profile.
Comparing Connection Methods and Troubleshooting
Various topologies and equipment can be used to set up a local area network without internet access. Below is a table comparing the main implementation options to help you choose the best one for your needs.
| Connection method | Transfer speed | Stability | Difficulty of setup |
|---|---|---|---|
| Wi-Fi (2.4 GHz) | Low/Medium | Average | Low |
| Wi-Fi (5 GHz) | High | High | Low |
| Ethernet cable (100 Mbps) | Average | Very high | Medium (requires cables) |
| Ethernet cable (1 Gbps) | Maximum | Very high | Medium (requires cables) |
If the devices don't see each other, first check that the command works pingOpen the command prompt and type ping 192.168.1.XX (target device address). If there's a response ("Reply from..."), the physical connection and IP settings are correct, and the problem lies with the Windows Firewall or antivirus settings. Antivirus programs often block the local network, considering it "public."
Another common issue is using different workgroups. While this is less of a concern in modern versions of Windows, it's still a good idea to have all computers set to the same workgroup (by default). WORKGROUP). You can check this in System Properties. Also, make sure that SMB v1 services are disabled (they are insecure), but SMB v2 and v3 are enabled.
⚠️ Note: Router interfaces from different manufacturers (ASUS, TP-Link, D-Link, Zyxel) may have different menu layouts. Look for sections with similar names, such as "Local Area Network," "LAN," "DHCP," or "Wireless." The setup logic is the same for all devices.
Frequently Asked Questions (FAQ)
Is it possible to play online games over such a local network?
Yes, absolutely. Most games, both old and new, support LAN (Local Area Network) mode. If the game detects network adapters and has access to IP addresses, it can connect players through the router without internet access. This is the perfect way to host a Counter-Strike, Minecraft, or Warcraft tournament without straining your ISP's bandwidth.
Will Chromecast or AirPlay work without internet?
Functionality will be limited. Screen mirroring often works, so