Dhcp Snooping; C Ha Pte R 27 Dhc P Sno O Ping; Dhcp Snooping Overview; What You Can Do - ZyXEL Communications GS2220 Series User Manual

27.1 DHC P Sno o ping O ve rvie w
With DHCP snooping, the Switch can build the binding table dynamically by snooping DHCP packets
(dynamic bindings) and filter unauthorized DHCP packets in your network.
The Switch uses a binding table to distinguish between authorized and unauthorized DHCP packets in
your network. A binding contains these key attributes:
• MAC address
• VLAN ID
• IP address
• Port number
When the Switch receives a DHCP packet, it looks up the appropriate MAC address, VLAN ID, IP
address, and port number in the binding table. If there is a binding, the Switch forwards the packet. If
there is not a binding, the Switch discards the packet.
27.1.1 Wha t Yo u C a n Do
• Use the
DHC P Sno o ping
snooping database.
• Use this
DHC P Sno o ping C o nfig ure
the Switch (not on specific VLAN), specify the VLAN where the default DHCP server is located, and
configure the DHCP snooping database.
• Use the
DHC P Sno o ping Po rt C o nfig ure
are trusted or untrusted ports for DHCP snooping.
• Use the
DHC P Sno o ping VL AN C o nfig ure
snooping on each VLAN and to specify whether or not the Switch adds DHCP relay agent option 82
information to DHCP requests that the Switch relays to a DHCP server for each VLAN.
• Use the
DHC P Sno o ping VL AN Po rt C o nfig ure
DHCP option 82 profile to certain ports in a VLAN.
DHC P Sno o ping
27.2
Use this screen to look at various statistics about the DHCP snooping database.
To open this screen, click
.
Sno o ping
Chapter 27 DHCP Snooping
DHC P Sno o ping
screen (Section 27.2 on page
screen (Section 27.3 on page
screen (Section 27.3.1 on page
screen
screen
>
Adva nc e d Applic a tio n
GS2220 Series User's Guide
263
C
HA PTER
263) to look at various statistics about the DHCP
266) to enable DHCP snooping on
267) to specify whether ports
(Section 27.3.2 on page 268) to enable DHCP
(Section 27.3.3 on page
>
IP So urc e G ua rd IPv4 So urc e G ua rd Se tup
2 7
269) to apply a different
>
DHC P