Command Reference Guide

68 ● dhcp relay release 3Com Router 5000 Family and Router 6000 Family
Command Reference
dhcp relay release
Purpose Use the dhcp relay release command to send an IP address releasing request to
a DHCP server via the DHCP relay.
Syntax dhcp relay release { client-ip mac-address } [ server-ip ]
Parameters client-ip
IP address of the DHCP client.
mac-address
MAC address of the DHCP client, which is in the
format of H-H-H.
server-ip
IP address of the DHCP server.
Example Send a release packet to the DHCP server at 10.110.91.174, requesting to release the
IP address 192.2.2.25, which was offered to the client whose MAC address is
0050-ba34-2000.
[3Com] dhcp relay release 192.2.2.25 0050-ba34-2000 10.110.91.174
View This command can be used in the following views:I
■ Interface view
■ System view
Description In the event no IP address of DHCP server has been specified, release packets would
be sent either to all the DHCP servers if this command is configured in system view or
to all the relay addresses configured on an interface if this command is configured in
interface view.
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.
A release request takes effect only when the server uses MAC address to identify
users. The DHCP server function of a 3Com router uses MAC address to identify
users, while those from most manufactures uses ID.
No debugging information is printed upon execution of this command.