Router DHCP Not Assigning IPs? Causes and Fixes

What DHCP does and the signs it failed

DHCP stands for Dynamic Host Configuration Protocol. The router runs a DHCP server that hands out private IP addresses to phones, laptops, streaming boxes, and other devices on your LAN. The server keeps a pool of available addresses and assigns one to each device for a limited lease. Without a lease, a device cannot speak to the rest of the network using normal IP routing. For a deeper look at the protocol, see DHCP explained.

The clearest sign of a failed DHCP assignment is a device that connects to Wi-Fi but shows no usable network. It may report no internet access, a self-assigned address, or an error about an IP configuration. Different operating systems word this differently, but the result is the same: the device has no valid lease from the router. Check the router's connected-device list to see whether the device appears without an address or stays in a pending state. If it does, DHCP is likely the problem.

Check the basic DHCP settings first

Log into the router's admin page when you need to inspect DHCP. Many routers keep the DHCP server enable switch under a LAN section. Open that page and confirm the server is on. If someone disabled it in the past, every device that requests a new lease will be unable to get an address. Details vary by router, but the same setting is usually easy to find.

Also look at the pool range and the number of addresses available. If the pool is small or the subnet mask limits it, a full pool will reject new clients even though the router is working. Expanding an available IP range inside the same subnet, or freeing up addresses by removing unused devices, often resolves the issue. When you need a hand finding the right section, logging into the router admin page is the first step.

• Confirm the DHCP server is enabled.
• Review the starting and ending IP addresses in the pool.
• See how many devices are already using the pool.
• Use the router's release or disconnect control to remove a stuck client.

Review lease time, reservations, and static IP conflicts

DHCP leases are not permanent. Each device must renew before the lease expires. If the lease time is very short and the router is busy or reboots often, some clients may fail to renew and lose their address. On a stable home network, a longer lease reduces unnecessary renewal traffic. You can read more about how renewal timing works in DHCP lease time explained.

DHCP reservations and static IPs are both ways to give a device a predictable address. A reservation is the safer choice because the router manages the assignment. If you use a static IP, place it outside the DHCP pool; an address that falls inside the pool can later be handed to another device, creating an IP address conflict. This is a common cause of devices dropping off the network. See the difference between DHCP reservations and static IPs and how to handle an IP address conflict.

If you recently changed your LAN subnet or moved the router from another home, old static addresses on laptops, printers, and NAS devices may no longer match the current network. A device configured for a different subnet will not accept a DHCP offer from the router.

Make sure only one DHCP server runs on the network

If your home has more than one device acting as a router, multiple DHCP servers can hand out addresses from different ranges. The result is unpredictable: a device gets an address from one server while the default gateway belongs to another, so traffic stalls. This often happens when people keep the ISP gateway in router mode and add another router behind it. You can learn more about that setup in ISP router vs your own router.

The clean fix is to choose a single device to handle DHCP. Put the other router in bridge mode or access point mode, or turn off DHCP on the secondary device. In a mesh system, the primary node should be the only DHCP server, and satellites should operate in a managed mode. For more details, see bridge mode explained.

• Use a single router as the DHCP server.
• Set the other router to bridge mode or access point mode.
• Keep the ISP gateway in router mode only if it controls the network.
• Check that no old router is still connected and enabled.

Reboot, update, and reset when needed

A quick reboot fixes many DHCP failures because it clears the router's temporary state, including the running DHCP server table. Power off the router for a few seconds, then power it back on. If the modem is separate, restart the network in order: modem first, then router. Use a proper router reboot procedure so you do not lose your settings.

If reboots do not help, update the router firmware. Some DHCP problems come from bugs in the router's DHCP implementation, and vendors publish updates to correct them. Keep the firmware on the latest stable version to reduce the chance of a repeat failure. You can follow a firmware update guide to do this safely.

Factory reset is a last resort. It restores the router's DHCP settings, but it also erases Wi-Fi names, passwords, and port forwarding rules. Back up your configuration if the router supports it before resetting, and be prepared to set up the network again. If you decide to go that far, factory resetting the router is the final step in the troubleshooting order.

Secure the router while you troubleshoot

While you are in the router settings, use the opportunity to review basic security. Change the administrator password, keep the firmware updated, and use current Wi-Fi security. Wi-Fi Alliance notes that WPA3 is mandatory for Wi-Fi CERTIFIED devices and that protected management frames are required for all new certified devices. Support for WPA3 is a good sign when you compare routers. See WPA3 explained for more.

Router maintenance is part of broader cybersecurity hygiene. NIST publishes standards, guidelines, and best practices for cybersecurity and privacy, and its Small Business Cybersecurity Corner collects resources aimed at smaller networks. You do not need an enterprise setup at home, but keeping the router secure reduces the chance that a DHCP or connection problem is caused by something more serious.

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Questions

Why does my device connect to Wi-Fi but show no internet?

The device may not have received an IP address from the router's DHCP server. Confirm DHCP is enabled, check the pool, and reboot the router. The device may also need to forget the network and reconnect.

How do I know if my router's DHCP server is off?

Open the router admin page and look for the LAN, network, or DHCP section. Most routers show a checkbox or toggle for the DHCP server. If it is off, enable it and save the settings.

Can too many devices cause a router to stop assigning IP addresses?

Yes. If every address in the DHCP pool is in use, new devices cannot get a lease. Remove unused devices, extend the pool if your subnet permits, or use DHCP reservations to manage important devices.

What is the difference between a DHCP reservation and a static IP address?

A reservation binds a device's MAC address to a specific IP address inside the DHCP server. A static IP is configured manually on the device. Reservations are easier to manage and avoid conflicts when set up correctly.

Should I use a longer or shorter lease time?

For a stable home network, a longer lease reduces renewal traffic and makes temporary outages less disruptive. For a guest network with many short visits, a shorter lease helps recycle addresses. Match the lease time to how often devices join the network.

What should I do if another router is causing DHCP conflicts?

Turn off DHCP on the secondary router or set it to bridge mode or access point mode. Only the primary router should assign IP addresses.