H3C S3600 Series Operation Manual

Also see for H3C S3600 Series: Datasheet Installation manual Command manual Operation manual Command manual

Contents

H3C S3600 Series Operation Manual Manual pdf 9 page image

Operation Manual – DHCPH3C S3600 Series Ethernet Switches-Release 1510 Chapter 2 DHCP Server Configuration2-2directly forwarded by hardware instead of being delivered to the DHCP server, orbeing redirected to the master unit by UDP HELPER. This idles the DHCP server.DHCP packets can be redirected to the DHCP server on the master unit by UDPHELPER only when the Layer 2 device is upgraded to a Layer 3 device.Caution:z When you merge two or more IRF systems into one IRF system, a new master unitis elected, and the new IRF system adopts new configurations accordingly. Thismay result in the existing system configurations (including the address poolsconfigured for the DHCP servers) being lost. As the new IRF system cannot inheritthe original DHCP server configurations, you need to perform DHCP serverconfigurations for it.z When an IRF system is split into multiple new IRF systems, some of the new IRFsystems may be degraded to Layer 2 devices. For a new IRF system degraded toLayer 2 device, although the original DHCP server still exists in the new system, itruns idle for being unable to receive any packets. When the IRF system restores toa Layer 3 device due to being merged into a new IRF system, it adopts theconfigurations on the new IRF system. And you need to perform DHCP serverconfigurations if the new IRF system does not have DHCP server-relatedconfigurations.z In an IRF system, the UDP HELPER function must be enabled on the DHCP serversthat are in fabric state.2.1.3 DHCP Address PoolA DHCP address pool holds the IP addresses to be assigned to DHCP clients. When aDHCP server receives a DHCP request from a DHCP client, it selects an address pooldepending on the configuration, picks an IP address from the pool and sends the IPaddress and other related parameters (such as the IP address of the DNS server, andthe lease time of the IP address) to the DHCP client.I. Types of address poolThe address pools of a DHCP server fall into two types: global address pool andinterface address pool.z A global address pool is created by executing the dhcp server ip-pool commandin system view. It is valid on the current device.z If an interface is configured with a valid unicast IP address, you can create aninterface-based address pool for the interface by executing the dhcp selectinterface command in interface view. The IP addresses an interface address pool