Cisco 500 series Administration Manual page 388

Configuring DHCP
Interactions Between DHCP Snooping, DHCP Relay and Option 82
Cisco 500 Series Stackable Managed Switch Administration Guide
DHCP Relay
VLAN with IP Address
Packet is sent
Option 82
insertion without
disabled Option 82
Packet is sent
Option 82
insertion without
enabled Option 82
DHCP Relay
VLAN without IP Address
Packet is sent
Relay –
with the discards
original Option 82
Option 82
Bridge –
Packet is sent
without
Option 82
Relay – Relay –
Packet is sent
discards
without Option 82
Option 82
Bridge –
Packet is sent
Bridge –
Packet is sent
without
with the Option 82
Option 82
23
Relay –
1. If reply
originates in
switch, packet
is sent without
Option 82
2. If reply
does not
originate in
switch, packet
is discarded
Bridge –
Packet is sent
with the
original
Option 82
Relay –
Packet is sent
without
Option 82
Bridge –
Packet is sent
with the
Option 82
388