Chapter 83 Dhcp Snooping; Dhcp Snooping Overview; What You Can Do; Dhcp Snooping Status - ZyXEL Communications XS3800-28 User Manual

83.1 DHCP Snooping Overview

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.
With DHCP snooping, the Switch can block a DHCP server on a snooped VLAN that comes from an
untrusted port in your network.

83.1.1 What You Can Do

• Use the DHCP Snooping Status screen
DHCP snooping database.
• Use this DHCP Snooping Setup screen
Switch (not on specific VLAN), specify the VLAN where the default DHCP server is located, and
configure the DHCP snooping database.
• Use the DHCP Snooping Port Setup screen
trusted or untrusted ports for DHCP snooping.
• Use the DHCP Snooping VLAN Setup screen
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 DHCP Snooping VLAN Port Setup screen
option 82 profile to certain ports in a VLAN.

83.2 DHCP Snooping Status

Use this screen to look at various statistics about the DHCP snooping database.

Chapter 83 DHCP Snooping

C
DHCP Snooping
(Section 83.2 on page
(Section 83.3 on page
(Section 83.4 on page
(Section 83.5 on page
(Section 83.6 on page
XS3800-28 User's Guide
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H A P T E R
609) to look at various statistics about the
612) to enable DHCP snooping on the
613) to specify whether ports are
615) to enable DHCP snooping on
616) to apply a different DHCP
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