H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 70)

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Figure 25 Configure trusted ports in a cascaded network
Table 4 describes the roles of the ports shown in Figure 25 .
Table 4 Roles of ports
Device Untrusted port
Trusted port disabled from
recording binding entries
Trusted port enabled to
record binding entries
Switch A GigabitEthernet 1/0/1 GigabitEthernet 1/0/3 GigabitEthernet 1/0/2
Switch B
GigabitEthernet 1/0/3 and
GigabitEthernet 1/0/4
GigabitEthernet 1/0/1 GigabitEthernet 1/0/2
Switch C GigabitEthernet 1/0/1
GigabitEthernet 1/0/3 and
GigabitEthernet 1/0/4
GigabitEthernet 1/0/2
DHCP snooping support for Option 82
Option 82 records the location information of the DHCP client so the administrator can locate the DHCP
client for security control and accounting purposes.
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 Table 5 .
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.