PLANET WGSW-52040 - Manual (Page 302)

ip dhcp snooping information
option subscriber-id {standard |
<circuit-id>}
no ip dhcp snooping information
option subscriber-id
Set the suboption1 (circuit ID option) content of
option 82 added by DHCP request packets (they
are received by the port). The no command sets
the additive suboption1 (circuit ID option) format
of option 82 as standard.
Command Explanation
Globe mode
ip dhcp snooping information
option allow-untrusted (replace|)
no ip dhcp snooping information
option allow-untrusted (replace|)
This command is used to set that allow
untrusted ports of DHCP snooping to receive
DHCP packets with option82 option. When the
"replace" is setting, the potion82 option is
allowed to replace. When disabling this
command, all untrusted ports will drop DHCP
packets with option82 option.
36.3 DHCP Snooping Typical Application
Figure 36-1: Sketch Map of TRUNK
As showed in the above chart, Mac-AA device is the normal user, connected to the non-trusted
port 1/1 of the switch. It operates via DHCP Client, IP 1.1.1.5; DHCP Server and GateWay are
connected to the trusted ports 1/11 and 1/12 of the switch; the malicious user Mac-BB is
connected to the non-trusted port 1/10, trying to fake a DHCP Server（by sending DHCPACK）.
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