Expanding the coverage area of a wireless network often becomes a necessity in modern conditions, when the walls of a house are made of materials that block radio signals. Device D-Link DSL-2640UOriginally designed as an ADSL modem, the device now features functionality that allows it to be used as a repeater or access point. This is an effective solution for recycling old equipment and improving connection quality in remote rooms without purchasing new, expensive systems.
The reconfiguration process requires careful attention, as the router's default firmware doesn't always include a one-click switch. You'll need to manually change the LAN settings, disable the DHCP server, and properly configure the wireless bridge. The key point The purpose here is to eliminate IP address conflicts within a single local network.
Before physically connecting the cables, you need to prepare your computer and study the current topology of your home network. Mistakes at the initial stage can lead to loss of access to the device's admin panel, requiring a complete reset. Therefore, proceed sequentially, verifying each step.
Preparing equipment and resetting settings
The first step is to prepare the hardware. Make sure you have an Ethernet cable and access to a computer with a network adapter. If the device was previously used by a provider or on a different network, it's crucial to perform a factory reset. This ensures there are no hidden configurations that could interfere with the new setup.
To reset, find the button on the back panel ResetPress it with a paperclip for 10-15 seconds until the indicators flash simultaneously. After rebooting, the router will return to its default settings, and the web interface will be accessible via the standard address.
⚠️ Please note: After resetting, all settings, including your ISP login and password (if saved), will be deleted. Make sure you have access to your ISP contract in case you need to restore your key settings.
Why is a reset necessary before reconfiguring?
Resetting removes old routing rules and MAC filters that could block the device from operating in its new repeater role. It also clears the DNS cache and ARP tables, ensuring a clean start to the configuration.
Connect your computer to one of the device's LAN ports using a cable. Avoid using the DSL/Line port, as it's often unused in repeater or access point mode or requires specific VLAN configuration, which complicates the process.
Logging into the web interface and changing the IP address
Open any browser and enter the standard IP address in the address bar. D-Link: 192.168.1.1To log in, use the standard credentials, usually login admin and the password field left blank, or also adminIf the standard data is not suitable, it is indicated on the sticker on the bottom of the case.
The most important step is changing the IP address of the router itself. If your default gateway (main router) has an address 192.168.1.1, That DSL-2640U will receive an address 192.168.1.1, a conflict will arise, and the network will become unstable. It is necessary to change the device's address to a free one, for example, 192.168.1.250.
To do this, go to the menu Setup → LANIn the field IP Address Enter the new address, making sure it is in the same subnet as the main router but does not overlap with the range of addresses issued by the main device's DHCP server. Save the changes by clicking Save/Apply.
After applying the settings, the connection to the computer will be lost. You will need to manually assign a static IP address to the PC's network card or simply reconnect to obtain an address from the main router and re-enter the interface using the new address.
Disabling the DHCP server
In repeater or access point mode, there should only be one address-distributing server running on the network. If you leave DHCP enabled on DSL-2640U, devices will receive incorrect gateway and DNS settings, which will result in a lack of internet access.
Find the section Setup → LAN or a separate tab DHCP Server. Set the switch to the position Disable or uncheck the box Enable DHCP ServerThis action transfers addressing authority to the master router.
- 📶 Make sure the DHCP range on the main router is large enough for all devices.
- 🔌 After disabling DHCP, it may take longer for your computer to reconnect.
- ⚙️ Don't forget to save the settings with the button
Savebefore leaving.
☑️ Check before disabling DHCP
After disabling the service, the device will stop issuing addresses to new devices but will continue to broadcast the network. This is a fundamental requirement for building a unified local network without addressing conflicts.
Setting up wireless mode and security
Go to the section Setup → WirelessHere you need to specify the network name (SSID). For seamless roaming, it is recommended to set the name identical to the network name on the main router. However, if you want to clearly differentiate devices, you can add a prefix, for example, Home_Ext.
Pay special attention to the security settings. In the section Wireless Security select encryption type WPA2-PSK (or WPA3, if your firmware supports it). The passphrase must match the primary network password if you want devices to automatically switch between access points.
The broadcast channel is an important parameter. To avoid interference, select a channel that isn't used by your main router or neighboring networks. For the 2.4 GHz band, channels 1, 6, and 11 are optimal.
| Parameter | Recommended value | Description |
|---|---|---|
| SSID | Primary_Network_Name | Identical to the main router for roaming |
| Channel | 1, 6 or 11 | Non-overlapping channels |
| Security | WPA2-PSK (AES) | Maximum compatibility and protection |
| Mode | 802.11 b/g/n | Mixed mode for older devices |
⚠️ Note: D-Link firmware interfaces may vary depending on the hardware version (S, U, RU, N). If you don't find the exact name of the item, look for similar options that include "Wireless," "WLAN," or "Wi-Fi."
Setting up a wired connection (LAN-to-LAN)
After software configuration, you need to properly connect the devices physically. An Ethernet cable from the main router (from any LAN port) should be connected to any LAN port on the device. DSL-2640UThe DSL/Line port is not used in this circuit.
This LAN-to-LAN connection scheme turns the modem into a simple switch with access point functionality. All devices connected to both routers will be on the same subnet and can see each other (printers, NAS, media servers).
If you connect a cable to a DSL port, the device will attempt to establish a PPPoE connection or act as a bridge, which will prevent you from expanding your existing network without complex tunnel setup. Therefore, use only local network ports.
Checking operation and diagnosing problems
After connecting the cable, the LAN indicator on both devices should light up or blink. Connect your smartphone or laptop to the created Wi-Fi network and check for internet access. Try walking around your home: the device should switch between access points, although on older models this may occur with a noticeable delay.
Check the IP address received by the client. It should be issued by the main router, not DSL-2640UAlso check access to local network resources, such as a network printer or shared folders.
If you have internet access but the speed is slow, try repositioning your antennas or selecting a different wireless channel. Metal objects, mirrors, and microwave ovens can significantly reduce the signal quality in the 2.4 GHz band.
What should I do if I can't access the web interface after changing my IP?
You need to reset your network adapter settings to automatic (DHCP) and reconnect the cable. If this doesn't help, use the D-Link Click'n'Connect utility or perform a full reset using the Reset button and start the setup again.
Can the DSL-2640U be used as a full-fledged over-the-air repeater?
Most firmware versions for this model do not support WDS (Wireless Distribution System) mode for wireless network expansion. The device operates as a wired access point.
Why did my Wi-Fi speed drop after setting up a second router?
It's possible that both routers are operating on the same channel, causing interference. Speeds can also drop if the devices are too far apart and the signal between them is unstable.
Do I need to set up WPS to connect?
WPS isn't required for the network to work. However, if you want to quickly connect new devices, you can enable WPS in the Wireless section. The passwords must match on both routers.