11.1 About the Dynamic Host Configuration Protocol

The Dynamic Host Configuration Protocol (DHCP) allows client systems to obtain network configuration information from a DHCP server each time that they connect to the network. The DHCP server is configured with a range of IP addresses and other network configuration parameters that clients need.

When you configure an Oracle Linux system as a DHCP client, the client daemon, dhclient, contacts the DHCP server to obtain the networking parameters. As DHCP is broadcast-based, the client must be on the same subnet as either a server or a relay agent. If a client cannot be on the same subnet as the server, a DHCP relay agent can be used to pass DHCP messages between subnets.

The server provides a lease for the IP address that it assigns to a client. The client can request specific terms for the lease, such as the duration. You can configure a DHCP server to limit the terms that it can grant for a lease. Provided that a client remains connected to the network, dhclient automatically renews the lease before it expires. You can configure the DHCP server to provide the same IP address to a client based on the MAC address of its network interface.

The advantages of using DHCP include:

  • centralized management of IP addresses

  • ease of adding new clients to a network

  • reuse of IP addresses reducing the total number of IP addresses that are required

  • simple reconfiguration of the IP address space on the DHCP server without needing to reconfigure each client

For more information about DHCP, see RFC 2131.