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Enhancements
Release L.10.09 Enhancements
If DHCP snooping is enabled on a switch where an edge switch is also using DHCP snooping, it is
desirable to have the packets forwarded so the DHCP bindings are learned. To configure the policy
for DHCP packets from untrusted ports that already have Option 82 present, enter this command in
the global configuration context.
N o t e
The default
drop
policy should remain in effect if there are any untrusted nodes, such as clients,
directly connected to this switch.
Syntax:
[no] dhcp-snooping option 82 [remote-id <mac | subnet-ip | mgmt-ip>]
[untrusted-policy <drop | keep | replace>]
Enables DHCP Option 82 insertion in the packet.
remote-id
Set the value used for the
remote-id
field of the
relay information option.
mac:
The switch mac address is used for the
remote-id. This is the default.
subnet-ip:
The IP address of the VLAN the packet
was received on is used for the remote-id. If
subnet-ip
is specified but the value is not set, the
MAC address is used.
mgmt-ip:
The management VLAN IP address is
used as the remote-id.
If
mgmt-ip
is specified but
the value is not set, the MAC address is used.
untrusted-
policy
Configures DHCP snooping behavior when
forwarding a DHCP packet from an untrusted
port that already contains DHCP relay informa-
tion (Option 82). The default is
drop
.
drop:
The packet is dropped.
keep:
The packet is forwarded without replacing
the option information.
replace:
The existing option is replaced with a
new Option 82 generated by the switch.
