3Com S7906E - Switch, Руководство по настройке

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You can enable DHCP snooping to support Option 82 on Layer 2 Ethernet interfaces,ONU port
and Layer 2 aggregation interfaces only.
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If a Layer 2 Ethernet interface is added to an aggregation group, enabling DHCP snooping to
support Option 82 on the interface will not take effect. After the interface quits the aggregation
group, the configuration will be effective.
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To support Option 82, it is required to perform related configuration on both the DHCP server and
the device enabled with DHCP snooping. Refer to Configuring the Handling Mode for Option 82 for
DHCP server configuration of this kind.
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If the handling strategy of the DHCP-snooping-enabled device is configured as replace , you need
to configure a padding format for Option 82. If the handling strategy is keep or drop , you need not
configure any padding format.
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If the Option 82 is padded with the device name (sysname) of a node, the device name must
contain no spaces. Otherwise, the DHCP-snooping-enabled device will drop the message.
Displaying and Maintaining DHCP Snooping
To do… Use the command… Remarks
Display DHCP snooping entries
display dhcp-snooping [ ip
ip-address ]
Available in any view
Display Option 82 configuration
information on the DHCP snooping
device display dhcp-snooping
information
{ all | interface
interface-type interface-number }
Available in any view
Display DHCP packet statistics on the
DHCP snooping device (for distributed
devices)
display dhcp-snooping packet
statistics
[ slot slot-number ]
Available in any view
Display DHCP packet statistics on the
DHCP snooping device (for distributed
IRF devices)
display dhcp-snooping packet
statistics
[ chassis
chassis-number slot
slot-number
]
Available in any view
Display information about trusted ports display dhcp-snooping trust Available in any view
Clear DHCP snooping entries
reset dhcp-snooping { all | ip
ip-address }
Available in user view
Clear DHCP packet statistics on the
DHCP snooping device (for distributed
devices)
reset dhcp-snooping packet
statistics
[ slot slot-number ]
Available in user view
Clear DHCP packet statistics on the
DHCP snooping device (for distributed
IRF devices)
reset dhcp-snooping packet
statistics
[ chassis
chassis-number slot
slot-number
]
Available in user view