ipAutomatic configuration
DHCP can provide a client with an IP address and connection settings such as a gateway. Home routers commonly perform this role. An address is leased for a period that the client can renew. Renewal does not necessarily mean receiving a different address.
What a reservation does
A DHCP reservation can help a printer or local server keep a stable address. The router attempts to assign the designated address to the same client. This does not make your public internet IP static. For manual assignment, check for address conflicts and an incorrect subnet mask.
When a connection fails
Check the client’s assigned address, gateway, and DNS settings first. Failing to obtain an address can involve wireless connectivity, the DHCP server, or pool capacity. Testing one client instead of resetting every device at once makes it easier to locate the failing layer.
When a printer address changes
If a printer receives a new local address after reconnecting, identify the client on the router and consider a DHCP reservation. Check that another device is not using the intended address. A changed client identifier may affect the reservation. Reconnect the printer and inspect its assigned address; a public IP lookup cannot verify this local setting.
Further reading
DHCP — RFC 2131 ↗Put it into practice
Inspect one public IP, or compare a list of addresses with the bulk lookup tool. Location results are approximate.
Single lookup ↗ Bulk lookup ↗