DHCP binding database
Client MAC address
Port number
VLAN identifier
Leased IP address
Lease time
Syntax:
[no] dhcp-snooping database [file <tftp://<ip-address>/<ascii-string>>][delay <15-86400>][timeout <0-86400>]
file
Must be in Uniform Resource Locator (URL) format – “tftp://ip-address/ascii-string”. The maximum filename length is 63 characters.
delay
Number of seconds to wait before writing to the database. Default = 300 seconds.
timeout
Number of seconds to wait for the database file transfer to finish before returning an error. A value of zero (0) means retry indefinitely. Default = 300 seconds.
A message is logged in the system event log if the DHCP binding database fails to update. To display the contents of the DHCP snooping binding database, enter this command.
Syntax:
show dhcp-snooping binding
DHCP snooping binding database contents
switch(config)# show dhcp-snooping binding MacAddress IP VLAN Interface Time left ------------- --------------- ---- --------- --------- 22.22.22.22.22.22 10.0.0.1 4 6 1600
If a lease database is configured, the switch drops all DHCP packets until the lease database is read. This only occurs when the switch reboots and is completed quickly. If the switch is unable to read the lease database from the tftp server, it waits until that operation times out and then begins forwarding DHCP packets.