3Com 4500 PWR 26-Port Configuration Manual page 492

The address-che
agent. That is, the invalid a
of whether other comm
Before executing the a
server, you need to
server. Otherwise, the DHCP client will fail to obtain an IP address.
Configuring the d ynamic client address entry updating function
After relaying an IP address from th
automatically record the client's IP-to-MAC binding and generate a dynamic address entry. But as a
D HCP relay agent does not process DHCP-RELEASE packets, which are sent to DHCP servers by
DHCP clients through unicast when the DHCP client
maintained by the DHCP cannot be updated in time.
relay agent handshake function and configuring the dynamic client address entry updating interval.
After the handshake function is enabled, the DHCP relay agent sends the handsh
DHCP-REQUEST packet) periodically to the DHCP server using a client's IP address and its own MAC
address.
If the DHCP relay agent receives the DHCP-ACK packet from the DHCP server, or receives no
response from the server within a speci
relay agent ages out the corresponding entry in the client addre
If the DHCP r elay agent re
address d oes not expire. The DHCP rel
Follo w these steps to co
To do...
Enter system view
Enable the DHCP relay
agent hand shake
function
Set the interval at which
the DHCP relay agent
dynamically updates the
client address entries
Currently, the DHCP relay agent handshake function on an S4500 series switch can only interoperate
with a Window s 2000 DHCP server.
ck en able command is indepen
ddress check takes effect when this command is executed, regardless
a nds (such as the command t
d dress-check ena
configure the static binding of the IP addre
e DHCP server to the DHCP client, the DHCP relay agent can
fied period, the IP address can be assigned. The DHCP
ceives the DH CP-NAK packet from the DHCP serve
ay agent does not age o
nfigure the dynamic user
Use the command...
system-view
dhcp relay hand enable
dhcp-security tracker
{ interval | auto }
40-7
dent of other commands
o e nable DHC
ble command on the interface connected to the DHCP
ss to the MAC address of the DHCP
s release IP addresses, the user address entries
You can solve this problem by enabling the DHCP
ss table.
ut the corre
address entry upda ting functio
—
Optional
Enabled by default.
Optional
By default, auto is adopted, that is, the
interval is automatically calculated.
of the DHCP relay
P) are used.
ake packet (the
r, the lease of th
sponding ent ry.
n:
Remarks
e IP