User Manual
UMN:CLI
V8102
425
ip dhcp filter-address
MAC-
ADDR
Global
Blocks a MAC address in case of requesting IP ad-
dress.
MAC-ADDR: MAC address
ip dhcp filter-address
MAC-
ADDR
type
{
ack
|
decline
|
dis-
cover
|
inform
|
nak
|
offer
|
re-
lease
|
request
}
Blocks a MAC address with DHCP message type op-
tions.
no ip dhcp filter-address
MAC-ADDR
[
type
{
ack
|
decline
|
discover
|
inform
|
nak
|
offer
|
release
|
request
}]
Disables DHCP MAC filtering.
9.6.10.2
DHCP Server Packet Filtering
Dynamic Host Configuration Protocol (DHCP) makes DHCP server assign IP address to
DHCP clients automatically and manage the IP address. Most ISP operators provide the
service as such a way. At this time, if a DHCP client connects with the equipment that can
be the other DHCP server such as Internet access gateway router, communication failure
might be occurred.
DHCP filtering helps to operate DHCP service by blocking DHCP request which enters
through
subscriber’s port and goes out into uplink port or the other subscriber’s port and
DHCP reply
which enters to the subscriber’s port.
, server A has the IP area from 192.168.10.1 to 192.168.10.10. Suppose a
user connects with client 3 that can be DHCP server to A in order to share IP address
from 10.1.1.1 to 10.1.1.10.
Here, if client 1 and client 2 are not blocked from client 3 of DHCP server, client 1 and cli-
ent 2 will request and receive IP from client 3 so that communication blockage will be oc-
curred. Therefore, the filtering function should be configured between client 1 and client 3,
client 2 and client 3 in order to make client 1 and client 2 receive IP without difficulty from
DHCP server A.
