3Com Switch 8800 Configuration Guide Chapter 13 DHCP Configuration13-613.3 Configuring DHCP ServerThe following sections describe the DHCP server configuration tasks:z Creating a Global DHCP IP Address Poolz Configuring IP Address Assignment Modez Forbidding Specified IP Addresses to Be Automatically Assignedz Configuring Lease Time For DHCP Address Poolz Configuring DHCP Client Domain Namesz Configuring DNS Server Address for DHCP Clientsz Configuring NetBIOS Server Address for DHCP Clientsz Configuring NetBIOS Node Type for DHCP Clientsz Configuring Custom DHCP Optionsz Configuring Outbound Gateway Address for DHCP Clientsz Configuring Parameters for DHCP Server to Send Ping PacketsNote:Some of the above DHCP configurations can be performed for global IP address pools,IP address pool of current VLAN interface, or IP address pools of multiple specifiedVLAN interface respectively. They are:z Configuring lease time for DHCP address poolz Configuring DHCP client domain namesz Configuring DNS server address for DHCP clientsz Configuring NetBIOS server address for DHCP clientsz Configuring NetBIOS node type for DHCP clientsz Configuring DHCP custom options13.3.1 Creating a Global DHCP IP Address PoolAn IP address pool contains IP addresses that can be assigned to DHCP clients. Inresponse to DHCP request sent by a DHCP client, the DHCP server selects anappropriate IP address pool based on your configuration, choose an available IPaddress from the pool, and sends the IP address and other parameters (such as thelease time of the IP address) to the DHCP client. At present, you can configure up to128 global DHCP address pools for a DHCP server.The address pools of a DHCP server are hierarchically grouped like a tree. The rootholds the IP address of the network segment, the branches hold the subnet IPaddresses, and finally, the leaves hold the IP addresses of DHCP clients, which aremanually bound to the corresponding network adapters. Such a structure enablesconfigurations to be inherited. That is, configurations of the network segment can beinherited by its subnets, whose configurations in turn can be inherited by their clients.
