Assigns dynamic IP Addresses and provides other essential IP information, such as DNS servers and Default Gateway addresses. Configured per Subnet. Hosts can be configured manually; Servers usually are. Clients often depend on DHCP to “lend” them an IP Address Dynamic IP addresses are leased, and can expire. DHCP clients must renew their lease to maintain their claim to an IP address.
Acquiring a Dynamic IP
- Client Broadcasts a DHCPDISCOVER UDP message requesting an address
- A DHCP server will response with a DHCPOFFER message offering an IP address. It may assign an IP based on a preregistered MAC Address, or it may supply an address from a pool of addresses reserved for this purpose
- If the client accepts, it sends a DHCPREQUEST message for that address, this is because the client may get multiple offers from multiple DHCP servers (unlike me in this job market)
- The DHCP server responds back with a DHCPACK message and the client can begin to use this IP address