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Chapter 9. DHCP Servers

9.1. Why Use DHCP?
9.2. Configuring a DHCP Server
9.2.1. Configuration File
9.2.2. Lease Database
9.2.3. Starting and Stopping the Server
9.3. DHCP Relay Agent
9.3.1. Configure dhcrelay as a DHCPv4 and BOOTP relay agent
9.3.2. Configure dhcrelay as a DHCPv6 relay agent
9.4. Configuring a Multihomed DHCP Server
9.4.1. Host Configuration
9.5. DHCP for IPv6 (DHCPv6)
9.6. Additional Resources
9.6.1. Installed Documentation
Dynamic Host Configuration Protocol (DHCP) is a network protocol that automatically assigns TCP/IP information to client machines. Each DHCP client connects to the centrally located DHCP server, which returns the network configuration (including the IP address, gateway, and DNS servers) of that client.

9.1. Why Use DHCP?

DHCP is useful for automatic configuration of client network interfaces. When configuring the client system, you can choose DHCP instead of specifying an IP address, netmask, gateway, or DNS servers. The client retrieves this information from the DHCP server. DHCP is also useful if you want to change the IP addresses of a large number of systems. Instead of reconfiguring all the systems, you can just edit one configuration file on the server for the new set of IP addresses. If the DNS servers for an organization changes, the changes happen on the DHCP server, not on the DHCP clients. When you restart the network or reboot the clients, the changes go into effect.
If an organization has a functional DHCP server correctly connected to a network, laptops and other mobile computer users can move these devices from office to office.
Note that administrators of DNS and DHCP servers, as well as any provisioning applications, should agree on the host name format used in an organization. See Section 3.1.1, “Recommended Naming Practices” for more information on the format of host names.