User Manual

Table Of Contents
6.5.3 DHCP snooping port type setting
[Syntax]
ip dhcp snooping trust
no ip dhcp snooping trust
[Initial value]
None
[Input mode]
interface mode
[Description]
Sets the applicable interface as a trusted port for DHCP snooping.
If this command is executed with the "no" syntax, the setting returns to the default.
All ports are set as untrusted ports by default.
[Note]
This command can be specified only for the LAN/SFP ports and for logical interfaces.
This cannot be set for LAN/SFP ports that belong to a logical interface.
DHCP packet filtering is not performed with trusted ports, and trusted ports are set as ports to which trusted DHCP servers are
connected.
DHCP packet filtering is processed for untrusted ports as follows.
DHCP packets transmitted from the DHCP server are discarded.
Discard IP address release requests (DHCP RELEASE) and IP address duplicate detection notifications (DHCP DECLINE)
received from an interface whose MAC address is registered in the binding database and which is also dif
ferent from the
registered interface.
When MAC address verification is enabled, the MAC address for the DHCP packet transmission source is compared with
the client hardware database (chaddr). If the two do not match, the relevant DHCP packet is discarded.
When Option 82 is enabled and the Option 82 information is already added to the DHCP packet received from the DHCP
client, the relevant DHCP packet is discarded.
[Example]
This specifies port1.5 as a trusted port.
SWP2(config)#interface port1.5
SWP2(config-if)#ip dhcp snooping trust
6.5.4 Enable/disable setting for MAC address verification
[Syntax]
ip dhcp snooping verify mac-address
switch
no ip dhcp snooping verify mac-address
[Parameter]
switch : MAC address verification setting
Setting value Description
enable Enables MAC address verification setting
disable Disables MAC address verification setting
[Initial value]
ip dhcp snooping verify mac-address enable
[Input mode]
global configuration mode
[Description]
The MAC address for the transmission source of the DHCP packet received from an untrusted port is compared with the client
hardware database (chaddr). If the two do not match, the relevant DHCP packet is discarded.
If this command is executed with the "no" syntax, the setting returns to the default.
Command Reference | Layer 2 functions | 219