When a computer, phone, or router reports an IP configuration failure, it usually means the device is connected to Wi-Fi or Ethernet at the physical level but cannot obtain a valid network address. Without a proper IP address, subnet mask, gateway, and DNS settings, the device cannot communicate reliably with the internet or even with other devices on the local network. The problem can appear suddenly after a router restart, system update, driver change, or incorrect manual network setting.
TLDR: An IP configuration failure is most often caused by a router DHCP issue, a corrupted network setting, an outdated driver, or an incorrect manual IP address. Start by restarting the router and device, then renew the IP address and reset the network adapter. If the problem continues, check DHCP settings, DNS configuration, drivers, firewall software, and Ethernet hardware.
What “IP Configuration Failure” Means
Every device on a network needs a unique IP address. In most home and office networks, the router assigns this address automatically using DHCP, which stands for Dynamic Host Configuration Protocol. If DHCP fails, your device may show messages such as “Wi-Fi doesn’t have a valid IP configuration,” “Ethernet doesn’t have a valid IP configuration,” “Failed to obtain IP address,” or “Unidentified network.”
Sometimes the device assigns itself a temporary address, often beginning with 169.254. This is a sign that it could not get a proper address from the router. The connection icon may appear active, but internet access will not work because the device does not know where to send traffic.
1. Restart the Device and Router
The simplest fix is often the most effective. Restarting clears temporary errors in the router, modem, and network adapter.
- Turn off your computer, phone, or other affected device.
- Unplug the router and modem from power.
- Wait at least 60 seconds.
- Plug the modem in first, then the router.
- Wait until the lights are stable, then restart your device.
This process forces the router to refresh DHCP services and gives your device a new chance to request a valid IP address. If only one device is affected, the issue may be local to that device. If all devices fail, focus on the router, modem, or internet service.
2. Forget and Reconnect to the Wi-Fi Network
For Wi-Fi connections, saved network profiles can become corrupted or outdated. Removing the saved profile forces the device to create a fresh connection.
- Windows: Go to Settings > Network & Internet > Wi-Fi > Manage known networks, select the network, and choose Forget.
- macOS: Open System Settings > Wi-Fi > Details, then remove or forget the network.
- Android or iOS: Open Wi-Fi settings, tap the network, and choose Forget or Forget This Network.
Reconnect by selecting the network again and entering the password carefully. A wrong password usually causes an authentication error, but in some cases it can also lead to repeated connection failures.
3. Renew the IP Address
If the router is working but your device has kept an invalid address, renewing the IP lease can solve the problem.
On Windows: Open Command Prompt as administrator and run:
ipconfig /releaseipconfig /renewipconfig /flushdns
On macOS: Go to System Settings > Network, select Wi-Fi or Ethernet, open Details, then use the TCP/IP section to renew the DHCP lease.
On Linux: Depending on your distribution, you can restart NetworkManager or use DHCP client commands such as dhclient -r followed by dhclient.
If renewal fails repeatedly, the router may not be handing out addresses correctly, or the device may have a firewall, driver, or adapter problem.
4. Reset the Network Adapter
A network reset removes damaged configuration data and rebuilds the adapter settings. On Windows, go to Settings > Network & Internet > Advanced network settings > Network reset. After the reset, the computer will restart and you may need to reconnect to Wi-Fi and re-enter passwords.
You can also reset core network components from an administrator Command Prompt:
netsh winsock resetnetsh int ip reset
Restart the computer after running these commands. This can fix corrupted TCP/IP settings that prevent the adapter from receiving or using a valid IP configuration.
5. Check DHCP and Manual IP Settings
If your device is set to use a manual IP address, the address may conflict with another device or may not match the router’s network range. For most users, the safest setting is automatic addressing.
Check that these options are enabled:
- Obtain an IP address automatically
- Obtain DNS server address automatically
If you need a manual IP address, confirm that it matches the router’s subnet. For example, if the router is 192.168.1.1, your device may need an address such as 192.168.1.50, with a subnet mask of 255.255.255.0 and a default gateway of 192.168.1.1. Avoid using an address already assigned to another device.
6. Update or Reinstall Network Drivers
Outdated or damaged network drivers are a common cause of Ethernet and Wi-Fi IP configuration errors, especially after operating system updates. On Windows, open Device Manager, expand Network adapters, right-click the adapter, and select Update driver. If that does not help, choose Uninstall device, restart the computer, and allow Windows to reinstall it.
For best results, download drivers directly from the computer or motherboard manufacturer. Avoid unknown driver websites, as they may provide outdated, incompatible, or unsafe files.
7. Test Ethernet Cables, Ports, and Wi-Fi Signal
For Ethernet, a damaged cable or failing port can allow a partial connection while still preventing stable communication. Try a different Ethernet cable, another router port, or a direct connection to the modem if appropriate. Look for link lights near the Ethernet port; no light may indicate a cable, port, or adapter fault.
For Wi-Fi, move closer to the router and test again. Weak signal, interference, or overloaded wireless channels can interrupt DHCP communication. If the issue occurs only in one location, signal quality may be the real cause.
8. Review Security Software and VPNs
Firewalls, antivirus suites, VPN clients, and enterprise security tools can sometimes interfere with DHCP or DNS traffic. Temporarily disable a recently installed security program or VPN and test the connection. If the network works afterward, update the software or adjust its network filtering settings.
Do not leave security protection disabled permanently. The goal is to identify whether the software is involved, then correct the configuration safely.
9. Check the Router Configuration
If several devices have the same problem, sign in to the router’s administration page and confirm that DHCP server is enabled. Also check whether the DHCP address pool is large enough. For example, a pool that only allows ten addresses can run out in a home with phones, laptops, smart TVs, consoles, and smart home devices.
If the router has been running for years without firmware updates, check the manufacturer’s website or router interface for an update. Firmware updates can fix DHCP bugs, security issues, and stability problems.
When to Contact Your ISP or IT Support
Contact your internet service provider if the modem cannot connect, the router receives no WAN address, or all devices lose connectivity after basic troubleshooting. In an office, school, or managed building, contact IT support before changing manual IP settings, DNS servers, or router configuration.
An IP configuration failure is usually fixable without replacing hardware. Work logically: restart equipment, renew the IP address, reset the adapter, verify DHCP, and then investigate drivers, cables, security tools, and router settings. A careful step-by-step approach reduces guesswork and helps identify whether the fault is with the device, the local network, or the internet service itself.