What is DHCP and How Does It Work?

What is DHCP?

DHCP (Dynamic Host Configuration Protocol) is the system your router uses to automatically assign IP addresses to devices when they join your network. Without DHCP, you would need to manually configure a unique IP address on every device — a tedious process for households with many devices.

How DHCP Works

When a device joins your network (e.g., your phone reconnects to WiFi), it sends a broadcast message: 'I need an IP address!' The DHCP server (built into your router) responds with: 'Use IP address 192.168.1.50 for the next 24 hours.' This process is called a DHCP handshake (DORA: Discover, Offer, Request, Acknowledge).

DHCP Lease Time

IP addresses are assigned for a limited time called a 'lease'. When the lease expires, the device requests a renewal. If the device has left the network, the IP address is returned to the pool and can be given to another device. Default lease times are typically 24 hours for home routers.

DHCP Address Range

Your router's DHCP server assigns addresses from a defined range, for example 192.168.1.100 to 192.168.1.200. You can configure this range in the router admin panel under LAN Settings → DHCP Server.

Static vs Dynamic IP Addresses

DHCP assigns dynamic addresses — the same device may get a different IP on different connections. For devices where a consistent address matters (NAS drives, printers, security cameras), use DHCP reservations (also called static DHCP). This tells the DHCP server to always assign the same IP to a specific device based on its MAC address. This is more convenient than manually configuring a static IP on the device.

DHCP Settings in Your Router

To view and configure DHCP settings, log into your router admin panel and navigate to LAN Settings or DHCP Server. Here you can: view all connected devices and their assigned IPs, change the DHCP address range, set lease duration, and add DHCP reservations for specific devices.