Dhcp Snooping Support For Option 82 - H3C S5120-SI Series Configuration Manual

Figure 14 Configure trusted ports in a cascaded network
Table 3 describes roles of the ports shown in Figure 14.
Table 3 Roles of ports
Device
Switch A
Switch B
Switch C

DHCP snooping support for Option 82

Option 82 records DHCP client location information so the administrator can locate the DHCP client for
security control and accounting purposes.
If DHCP snooping supports Option 82, it handles a client's request according to the contents defined in
Option 82, if any. The handling strategies are described in Table 4.
If a reply returned by the DHCP server contains Option 82, the DHCP snooping device removes 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
GE1/0/1
GE1/0/3 and GE1/0/4
GE1/0/1
Trusted port disabled from
recording binding entries
GE1/0/3
GE1/0/1
GE1/0/3 and Ethernet 1/4
48
Trusted port enabled to
record binding entries
GE1/0/2
GE1/0/2
GE1/0/2