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23 DHCP Snooping
(2) Using the dynamic ARP inspection functionality
To use the dynamic ARP inspection, you need to set the following DHCP snooping
configurations to generate the binding database.
Configuration command
Configuration command
snooping is performed.
Dynamic ARP inspection also checks the entries that are statically registered in a binding
database by using the
(3) Notes on saving and restoring a binding database
If the save location has not been set with the
configuration command (initial status), the binding database will not be saved.
Therefore, restarting the Switch will erase the registered binding database, disabling
communication from DHCP clients. In this case, clear and update the IP addresses
on the DHCP client. In Windows, for example, execute
ipconfig /renew
This re-registers terminal information in the binding database and enables
communication by DHCP clients.
Entries that have exceeded the lease time of the DHCP server will not be restored.
After the binding database is saved, if the clock setting is changed before the Switch
is turned off, the restoration processing for the binding database might be performed
incorrectly after the Switch is turned on.
Restoration of the entries that were statically registered by the
configuration command is performed according to the startup configuration file at
startup.
If you have saved the binding database on a memory card, do not remove the
memory card until a prompt appears on the screen after the switch restarts.
Before executing the
executing the
ip dhcp snooping database url
save location on the device to which the database is being restored. If you execute
the
remains configured, the restoration processing of the binding database might be
performed incorrectly.
418
ip dhcp snooping
ip dhcp snooping vlan
ip source binding
from the command prompt.
backup
restore
operation command to restore the database, check that the
restore
operation command when the binding database location setting
: Enables DHCP snooping.
: Sets the VLANs for which DHCP
configuration command.
ip dhcp snooping database url
operation command to save the binding database and
configuration command has not been used to set a
ipconfig /release
and then
ip source binding
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