For most home devices, leave DHCP enabled. When a printer or server needs a predictable LAN address, a router DHCP reservation is usually easier to maintain than separate manual settings on the device. A fixed LAN address does not make your public IP static.
Three ways a device gets an address
DHCP supplies a lease and configuration such as a subnet mask, default gateway, and DNS servers. The address may be renewed or changed. A reservation tells the DHCP server to offer a particular address to a particular client identity. A manual static configuration stores those values on the device itself.
| Method | Good fit | Main pitfall |
|---|---|---|
| Ordinary DHCP | Laptops, phones, guests | Address may change |
| DHCP reservation | Printers, home servers | Client identity can change |
| Manual static LAN address | Infrastructure with documented requirements | Conflicts or stale gateway/DNS settings |
Build a small address plan
For a 192.168.20.0/24 LAN, you might use 192.168.20.1 for the gateway and a DHCP pool of .100–.199. A manually assigned printer at .20 stays outside that pool. A reservation can use a different arrangement depending on the router; some require reservations within the pool and others do not. Follow that router's documented behavior.
Do not choose the network address .0 or traditional broadcast .255 in this example. Check the actual prefix rather than assuming those endings are always special. Make a list of existing fixed addresses before assigning another.
Make the change and confirm it
- Record the current address, prefix/mask, gateway, DNS servers, and client identity.
- Create the reservation or carefully enter all manual settings.
- Reconnect the client or renew its DHCP lease when it is safe to interrupt connectivity.
- Confirm the actual assigned address, then test the gateway and a hostname.
On Windows, ipconfig /all shows configuration for each adapter. A working IP connection with failed name lookups often points toward DNS rather than the chosen address. A duplicate-address warning calls for checking other devices and the DHCP pool, not simply trying random addresses.
Reservations, Wi-Fi privacy, and public addresses
Private or randomized Wi-Fi MAC addresses can alter the identity a router uses for reservations. Check the per-network setting and router lease table instead of globally disabling a privacy feature without need. Moving to a different adapter can also create a different lease identity.
Your ISP controls the public address allocation. A router reservation only stabilizes an address inside your LAN. If a remote client needs to find a changing public address, investigate dynamic DNS separately; if incoming IPv4 is blocked by CGNAT, dynamic DNS alone does not solve that reachability problem.
Put it into practice
References & further reading
Protocol standards and official documentation supporting this guide. Device menus and provider policies vary; use the documentation for your equipment when applying a change.