Ruijie RG-S2900G-E Series, Configuration Manual

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Configuration Guide DHCP Configuration
DHCP Configuration
Introduction to DHCP
The DHCP (Dynamic Host Configuration Protocol), specified in RFC 2131,
provides configuration parameters for hosts over the Internet. The DHCP works
in the client/server mode. The DHCP server assigns IP addresses for the hosts
dynamically and provides configuration parameters.
The DHCP assigns IP address in three ways:
1. Assign IP addresses automatically. The DHCP server assigns permanent IP
addresses to the clients;
2. Assign IP addresses dynamically. The DHCP server assigns IP addresses
that will expire after a period of time to the clients (or the clients can release the
addresses by themselves);
3. Configure IP addresses manually. Network administrators specify IP
addresses and send the specified IP addresses to the clients through the
DHCP.
Among the above mentioned three methods, only dynamic assignment allows
reuse of the IP address that the client does not need any more.
The format of DHCP message is based on that of BOOTP (Bootstrap Protocol)
message. Hence, it is necessary for the device to be able to act as the BOOTP
relay agent and interact with the BOOTP client and the DHCP server. The
function of BOOTP relay agent eliminates the need of deploying a DHCP server
in every physical network. The DHCP is detailed in RFC 951 and RFC 1542.
Introduction to the DHCP Server
As specified in RFC2131, the DHCP server of Ruijie is implemented to assign
and manage IP addresses for the DHCP clients. The DHCP operation process
is shown in the following figure.