Release Client Ip Address Through Dhcp Relay; Configure Address Map Entry For Security Check - Huawei Quidway S3500 Series Operation Manual

Operation Manual - Network Protocol
Quidway S3500 Series Ethernet Switches

5.4.3 Release Client IP Address through DHCP Relay

Sometimes you may need to manually release the IP address allocated to a client
through the DHCP Relay.
Perform the following configuration in VLAN interface view or system view.
Table 5-33 Release client IP address by the DHCP Relay
Request the DHCP server for releasing
a client IP address
If no DHCP server is specified, the release request is sent to all DHCP servers in
system view but in VLAN interface view only to the DHCP servers of the current VLAN
interface.
Note:
After receiving an IP address release request from the DHCP relay, the DHCP server
releases the IP address from the IP-in-use address pool and moves it to the
lease-expired queue. Normally, this address will experience some time before
participating in allocation again. For the client, however, this address is not released
and will be used until its lease really expires.

5.4.4 Configure Address Map Entry for Security Check

To make the valid user with fixed IP address in the VLAN configured with DHCP Relay
pass the address validity check of DHCP security feature, you must add a static
address entry which indicates the correspondence between an IP address and an MAC
address.
If another illegal user configures a static IP address which is in conflict with the fixed IP
address of a valid user, the switch with DHCP Relay function enabled can identify the
valid user and reject the illegal user's request for binding the IP address with the MAC
address.
Perform the following configuration in system view.
Operation
Huawei Technologies Proprietary
5-21
Chapter 5 DHCP Configuration
Command
dhcp relay release
mac-address [ server-ip ]
client-ip