Dhcp Snooping Support For Option 82 - HP 1910 User Manual

In a cascaded network as shown in
connected to other DHCP snooping devices as trusted ports. To save system resources, you can disable
the untrusted ports that are not directly connected to DHCP clients from generating DHCP snooping
entries.
Figure 299 Trusted ports and untrusted ports in a cascaded network
Table 98 describes roles of the ports shown in
Table 98 Roles of ports
Device
Switch A
Switch B
Switch C

DHCP snooping support for Option 82

Option 82 records the location information of the DHCP client. The administrator can locate the DHCP
client to further implement security control and accounting. For more information, see
option (Option
If DHCP snooping supports Option 82, it will handle a client's request according to the contents defined
in Option 82, if any. The handling strategies are described in the table below.
If a reply returned by the DHCP server contains Option 82, the DHCP snooping device will remove the
Option 82 before forwarding the reply to the client. If the reply contains no Option 82, the DHCP
snooping device forwards it directly.
Untrusted port
GigabitEthernet 1/0/1
GigabitEthernet 1/0/3 and
GigabitEthernet 1/0/4
GigabitEthernet 1/0/1
82))."
Figure 299, configure each DHCP snooping device's ports
Figure 299.
Trusted port disabled from
recording binding entries
GigabitEthernet 1/0/3
GigabitEthernet 1/0/1
GigabitEthernet 1/0/3 and
GigabitEthernet 1/0/4
331
Trusted port enabled to
record binding entries
GigabitEthernet 1/0/2
GigabitEthernet 1/0/2
GigabitEthernet 1/0/2
"Relay agent