ZyXEL Communications IES-1248-51A, User Manual

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Chapter 54 DHCP Commands
IES-1248-51V User’s Guide
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54.6 DHCP Snoop Commands
Use these commands to configure or show DHCP snooping settings on the
subscriber ports. The system gets the client MAC-IP address information (in the
reply from a DHCP server) and stores it in the DHCP snooping table. The system
forwards packets from only the clients whose MAC-IP address is in the DHCP
snooping table. Packets from unknown IP address(es) are not forwarded
(dropped). This feature prevents clients from assigning their own static IP
addresses.
In some cases, you might want to allow packets from an IP address not offered by
the DHCP server. This might apply, for example, to static IP addresses. In this
case, you can specify the IP address whose packets are allowed, and the IES-
1248-51V forwards these packets as well.
Table 145 DHCP Snoop Commands
COMMAND DESCRIPTION P
switch dhcpsnoop enable < port-
list >
This command activates the DHCP snooping
feature on the specified port(s). M/
H
switch dhcpsnoop disable
< port-list >
This command disables the DHCP snooping
feature on the specified port(s). M/
H
switch dhcpsnoop flush < port-
list >
This command clears the DHCP snooping
binding table on the specified port(s). The
system also automatically clears the binding
table when you disable DHCP snooping. M/
H
switch dhcpsnoop lan2lan
disable
This command disables LAN to LAN DHCP
services. M/
H
switch dhcpsnoop lan2lan
enable
This command enables LAN to LAN DHCP
services. M/
H
switch dhcpsnoop lan2lan show
This command displays whether LAN to LAN
DHCP services are currently enabled or
disabled. M/
H
switch dhcpsnoop pool set
< port > < ip-address >
This command adds the specified IP address
to the static IP pool for the specified port.
The IES-1248-51V forwards packets from IP
addresses in this pool, as well as packets
from IP addresses learned through DHCP
snooping. You can set up to three IP
addresses for each port, but you have to set
each IP address for each port one at a time.
You cannot add IP addresses to a static IP
pool if the pool already has three IP
addresses in it. You have to delete one of the
existing IP addresses first.
port :
The selected ADSL port number(s).
M/
H