Enterasys C3G124-24 - Set Dhcpsnooping Binding

set dhcpsnooping binding
23-6 DHCP Snooping and Dynamic ARP Inspection
Usage
In order for DHCP snooping to operate, snooping has to be enabled globally and on specific
VLANs, and the ports within the VLANs have to be configured as trusted or untrusted. On
trusted ports, DHCP client messages are forwarded directly by the hardware. On untrusted ports,
client messages are given to the DHCP snooping application.
The DHCP snooping application builds the bindings database from client messages received on
untrusted ports. DHCP snooping creates a “tentative binding” from DHCP DISCOVER and
REQUEST messages. Tentative bindings tie a client to the port on which the message packet was
received. Tentative bindings are completed when DHCP snooping learns the client’s IP address
from a DHCP ACK message on a trusted port.
The ports on the switch through which DHCP servers are reached must be configured as trusted
ports so that packets received from those ports will be forwarded to clients. DCHP packets from a
DHCP server (DHCP OFFER, DHCP ACK, DHCP NAK) are dropped if received on an untrusted
port.
Example
This example configures port ge.1.1 as a trusted port.
C3
(rw)->set dhcpsnooping trust port ge.1.1 enable
set dhcpsnooping binding
Use this command to add a static DHCP binding to the DHCP snooping database.
Syntax
set dhcpsnooping binding mac-address vlan vlan-id ipaddr port port-string
Parameters
Defaults
None.
Mode
Switch command, read-write.
Usage
When enabled globally and on VLANs, DHCP snooping builds its bindings database from DHCP
client messages received on untrusted ports. Such entries in the database are dynamic entries
which will be removed in response to valid DECLINE, RELEASE, and NACK messages or when
the absolute lease time of the entry expires.
You can add static entries to the bindings database with this command.
mac-address Specifies the MAC address of the binding entry.
vlan vlan-id Specifies the VLAN of the binding entry.
ipaddr Specifies the IP address of the binding entry.
port port-string Specifies the port of the binding entry.