Cisco 500 series Administration Manual page 392

Configuring DHCP
DHCP Snooping Binding Database
Cisco 500 Series Stackable Managed Switch Administration Guide
Packet Type Arriving from
Untrusted Ingress
Interface
DHCPOFFER Filter.
DHCPREQUEST Forward to trusted
interfaces only.
DHCPACK Filter.
DHCPNAK Filter.
DHCPDECLINE Check if there is
information in the
database. If the
information exists and
does not match the
interface on which the
message was
received, the packet
is filtered. Otherwise
the packet is
forwarded to trusted
interfaces only, and
the entry is removed
from database.
DHCPRELEASE Same as
DHCPDECLINE.
DHCPINFORM Forward to trusted
interfaces only.
DHCPLEASEQUE Filtered.
RY
Arriving from Trusted Ingress
Interface
Forward the packet according to
DHCP information. If the
destination address is unknown
the packet is filtered.
Forward to trusted interfaces
only.
Same as DHCPOFFER and an
entry is added to the DHCP
Snooping Binding database.
Same as DHCPOFFER. Remove
entry if exists.
Forward to trusted interfaces only
Same as DHCPDECLINE.
Forward to trusted interfaces
only.
Forward.
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