Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 1429)

DHCP Snooping Introduction and Configuration
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C 55.7
Table 55-1: DHCP filtering on the switch
When the switch ... And ... Then the switch ...
DHCP packets
Receives a DHCP
BOOTP packet on a
trusted port Forwards the DHCP packet.
The packet contains a valid IP address lease
for a client, and the maximum number of
leases for the client port has not been
reached. Adds or updates a lease entry in the
DHCP snooping database.
The maximum number of leases for the client
port has been reached. Drops the DHCP packet, generates a
log message for the violation,
generates an SNMP notification
(trap), and does not add a lease entry
to the database.
A lease entry in the
DHCP snooping
database expires Removes the expired entry from the
database.
Receives a DHCP
BOOTP request packet
on an untrusted port The source MAC address and client hardware
address do not match. Drops the packet, generates a log
message for the violation, and sends
an SNMP notification (trap).
Receives a DHCP
BOOTP request packet
on an untrusted port The packet contains DHCP Relay Agent
Option 82 info. Drops the DHCP packet, generates a
log message for the violation, and
sends an SNMP notification (trap).
Receives a DHCP
BOOTP reply packet on
an untrusted port Drops the DHCP packet, generates a
log message for the violation, and
sends an SNMP notification (trap).
IP packets
Receives an IP packet
on a trusted port Forwards the IP packet.
Receives an IP packet
on an untrusted port Its source MAC address, IP address, and
receiving port match a valid lease entry in the
DHCP snooping database. Forwards the IP packet.
Receives an IP packet
on an untrusted port Its source MAC address, IP address, and
receiving port do not match a valid lease
entry in the DHCP snooping database. Drops the packet.
Does not generate a log message or
an SNMP notification.
ARP packets
Receives an ARP
request on a trusted
port Forwards the ARP packet.
Receives an ARP
request on an
untrusted port Its source MAC address, IP address, and
receiving port match a valid entry in the DHCP
snooping database Forwards the ARP packet.
Receives an ARP
request on an
untrusted port Its source MAC address, IP address, and
receiving port do not match an entry in the
DHCP snooping database Drops the packet, generates a log
message for the violation, and sends
an SNMP notification (trap).