Configuration Guide                                                                            Configuring DHCPConfiguring DHCP 
 
 
4.3  Features 
Basic Concepts   
  DHCP Server 
Based on the RFC 2131, Ruijie DHCP server assigns IP addresses to clients and manages these IP addresses. 
  DHCP Client 
DHCP Client enables a device to automatically obtain an IP address and configurations from a DHCP server. 
  DHCP Relay 
When a DHCP client and a DHCP server are not in a same subnet, they need a DHCP relay to forward DHCP request and 
reply packets.   
  Lease 
Lease is a period of time specified by a DHCP server for a client to use an assigned IP address. An IP address is active 
when leased to a client. Before a lease expires, a client needs to renew the lease through a server. When a lease expires 
or is deleted from a server, the lease becomes inactive.   
  Excluded Address 
An excluded address is a specified IP address not assigned to a client by a DHCP server. 
  Address Pool 
An address pool is a collection of IP addresses that a DHCP server may assign to clients. 
  Option Type 
An option type is a parameter specified by a DHCP server when it provides lease service to a DHCP client. For example, a 
public option include the IP addresses of a default gateway (router), WINS server and a DNS server. DHCP server allows 
configuration of other options. Though most options are defined in the RFC 2132, you can add user-defined options. 
Overview 
Enable DHCP Server on a device, and it may assign IP addresses dynamically and pushes 
configurations to DHCP clients. 
Enable  DHCP  Relay on  a  device,  and  it  may forward  DHCP  request  and  reply  packets 
across different network segments. 
Enable  DHCP  Client  on  a  device,  and  it  may  obtain  IP  addresses  and  configurations 
automatically from a DHCP server. 
Plan IP range requested by DHCP clients from different vlan+port/vlan   
4.3.1  DHCP Server 
Working Principle 
  DHCP Working Principle