Dhcp Snooping Filtering - SMC Networks 7824M/VSW - annexe 1 Manual

Management Guide
TigerAccess™ EE
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8.6.7.8
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SMC7824M/VSW
To specify a DHCP database agent and enable an automatic DHCP snooping database
back-up, use the following command.
Command
ip dhcp snooping database
A.B.C.D INTERVAL
no ip dhcp snooping database
To request snooping binding entries from a DHCP snooping database agent, use the fol-
lowing command.
Command
ip dhcp snooping database re-
new A.B.C.D
The DHCP snooping database agent should be TFTP server.

DHCP Snooping Filtering

If there are incoming packets to a port of switch enabled with DHCP snooping, it refers to
DHCP snooping binding table and filters these packets whether their information is regis-
tered in the table or not. DHCP snooping filtering function supports three modes that are
classified into filter, bypass and permit. Filter mode permits the registered packets only
according to DHCP snooping binding table. Both permit and bypass mode permits all
packets irrespective of DHCP snooping binding table. Both modes are written the filter en-
tries, but they do not filter packets. Permit mode uses a filter-delay timer to be changed to
filter mode. Otherwise, bypass mode uses a filter-delay counter.
DHCP snooping filter mode is not available in the system that is enabled with IP source
guard function.
To select one of DHCP snooping filter modes, use the following command.
Command
ip dhcp snooping filter-mode
PORTS { permit | bypass | filter }
no ip dhcp snooping filter-mode
PORTS
When the system is running in one of Permit and Bypass modes, the authorized ARP
function is not available.
Mode
Specifies a DHCP snooping database agent and back-
up interval.
A.B.C.D: DHCP snooping database agent address
Global
INTERVAL: 120-2147483637 (unit: second)
Deletes a specified DHCP snooping database agent.
Mode
Requests snooping binding entries from a DHCP
Global
snooping database agent.
A.B.C.D: DHCP snooping database agent address
Mode
Selects DHCP snooping filter mode and specifies an
action by DHCP snooping binding table
Global
Deletes the configured DHCP snooping filter mode.
Description
Description
Description
CLI
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