Dhcp Snooping Binding Database - Cisco SF500-24 Administration Manual

IP Configuration
IPv4 Management and Interfaces
Cisco 500 Series Stackable Managed Switch Administration Guide Release 1.3
The following describes how DHCP reply packets are handled when both DHCP
Snooping and DHCP Relay are enabled
DHCP Relay
VLAN with IP Address
Packet
arrives
without
Option 82
Option Packet is
82 sent without
Insertion Option 82
Disabled
Option Packet is
82 sent without
Insertion Option 82
Enabled

DHCP Snooping Binding Database

DHCP Snooping builds a database (known as the DHCP Snooping Binding
database) derived from information taken from DHCP packets entering the device
through trusted ports.
The DHCP Snooping Binding database contains the following data: input port,
input VLAN, MAC address of the client and IP address of the client if it exists.
DHCP Relay
VLAN without IP Address
Packet Packet
arrives with arrives
Option 82 without
Option 82
Packet is Relay
sent with the discards
original Option 82
Option 82
Bridge -
Packet is
sent without
Option 82
Packet is Relay –
sent without discards
Option 82 Option 82
Bridge –
Packet is
sent without
Option 82
17
Packet arrives with
Option 82
Relay
1. If reply originates
on the device,
packet is sent
without Option 82
2. If reply does not
originate on the
device, discards the
packet
Bridge – Packet is
sent with the
original Option 82
Packet is sent
without Option 82
300