Description Of The Dhcp Snooping Functionality - Alaxala AX2200S Series Configuration Manual

23 DHCP Snooping

23.1 Description of the DHCP snooping functionality

DHCP snooping monitors the DHCP packets that pass through the Switch to restrict access
from untrusted terminals.

With DHCP snooping, clients whose IP addresses have been assigned by DHCP
servers and terminals with fixed IP addresses are registered for management in a
binding database.

DHCP snooping suppresses IP address release requests from untrusted terminals
(terminals that have not been registered in the binding database; hereafter called
terminals not registered in the DB).

DHCP snooping prevents untrusted DHCP servers from handing out IP addresses.
To enable DHCP snooping, place the Switch between the DHCP server and DHCP clients
as shown in the following figure.
Figure 23-1 Overview of DHCP snooping
DHCP snooping also supports terminal filtering, which discards all the communication data
packets sent from terminals not registered in the DB.
DHCP snooping supports the following extended functionality, in addition to the above
functionality:

Forwarding DHCP packets with Option 82

Limiting the rate of DHCP packet reception

Dynamic ARP inspection

Saving a binding database
The following figure shows the relationship between the functionality and behavior of the
binding database.
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