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3-17-2. DHCP Snooping Entry
Function name:
DHCP Snooping Entry
Function description:
DHCP snooping Entry allows a switch to add the trust DHCP server and 2
trust ports to build the DHCP snooping available entry. This information can be
useful in tracking an IP address back to a physical port and enable or disable
the DHCP Option 82.
Parameter description:
VID：When DHCP snooping is enabled, and enabled on the specified
VLAN, DHCP packet filtering will be performed on any un-trusted
ports within the VLAN. It set an available VLAN ID to enable the
DHCP snooping on VLAN interface.
Trust Port 1：If DHCP snooping is enabled globally, and also enabled on
the VLAN where the DHCP packet is received, all DHCP packets are
forwarded for a trusted port. It set a trust port 1. available port from 0
to 24. 0 is disabled.
Trust port 2: It set a trust port 2. available port from 0 to 24. 0 is disabled.
Trust VID： It set a trust VLAN ID. available VID from 1 to 4094.
Server IP： It set a trust DHCP Server IP address for DHCP Snooping.
Option 82：It set the DHCP Option 82 function on the switch, default is
Disable.
Action：It set the switch when received a client DHCP request packet then
action for filtering. available action : keep/ drop / replace.
：
Note
Filtering rules are implemented as follows:
-
If the DHCP snooping is disabled, all DHCP packets are forwarded.
-
If DHCP snooping is enabled and also enabled on the VLAN where
the DHCP packet is received, all DHCP packets are forwarded for a
trusted port.
-
If DHCP snooping is enabled and also enabled on the VLAN where
the DHCP packet is received, but the port is not trusted, it is
Fig. 3-17-1 DHCP Snooping State
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