Using The Dhcp Relay Agent To Send A Dhcp-Release Request - H3C S5120-SI Series Configuration Manual

To configure dynamic binding update interval:
To do...
1. Enter system view
2. Enable periodic
refresh of dynamic
client entries
3. Configure binding
update interval
Enabling unauthorized DHCP servers detection
Unauthorized DHCP servers may assign wrong IP addresses to DHCP clients.
With unauthorized DHCP servers detection enabled, the DHCP relay agent records the IP address of each
DHCP server that it detects assigning an IP address to a requesting DHCP client. It also records the
receiving interface. The administrator can use this information to check for DHCP unauthorized servers.
To enable unauthorized DHCP server detection:
To do...
1. Enter system view
2. Enable unauthorized DHCP
server detection
The DHCP relay agent logs each detected DHCP server only once. After using this log information to find
unauthorized DHCP servers, the administrator clears the record so the relay agent makes new log entries.

Using the DHCP relay agent to send a DHCP-release request

This command allows you to use the DHCP relay agent to manually release a client's IP address. The
DHCP relay agent sends a DHCP-RELEASE message containing the client IP address to be released. Upon
receiving the DHCP-RELEASE message, the DHCP server releases the IP address for the client; meanwhile,
the client's IP-to-MAC binding entry is removed from the DHCP relay agent.
To use the DHCP relay agent in system view to send a DHCP-RELEASE request:
To do...
1. Enter system view
2. Configure the DHCP relay agent to send a
DHCP-RELEASE request
Use the command...
system-view
dhcp relay security
refresh enable
dhcp relay security
tracker { interval | auto }
Use the command...
system-view
dhcp relay server-detect
38
Remarks
—
Optional
Enabled by default.
Optional
auto by default. (auto interval is calculated by the
relay agent according to the number of bindings.)
Remarks
—
Required
Disabled by default.
Use the command...
system-view
dhcp relay release ip client-
ip
Remarks
—
Required