What does DHCP assign?
DHCP automates network configuration. A DHCPv4 server can provide an IPv4 address, subnet mask, default gateway, DNS servers and lease duration. A home router often performs this role; larger networks may use a dedicated server. DHCPv4 uses UDP port 67 on the server and 68 on the client.
The four DORA steps
During a typical initial assignment, Discover searches for a server, Offer proposes a configuration, Request asks for it and Acknowledge confirms the assignment. Renewals do not necessarily repeat all four steps. The lease is time-limited and is normally renewed before it expires.
Reservation or static address?
A reservation repeatedly assigns the same address to a client using the server's client identifier, often a MAC address. A manually configured address is independent of this process. It must fit the subnet and avoid conflicts. Randomized MAC addresses can affect reservations.
DHCP and IPv6
DHCPv6 uses UDP port 547 on the server and 546 on the client. IPv6 can also use SLAAC; Router Advertisements supply the default gateway in particular. DHCPv6 is therefore not an identical replacement for DHCPv4. Our public IP display cannot identify the DHCP server that assigned your local address.