PLANET LRP-822CS - Manual (Page 245)

User’s Manual of LRP-822CS
245
The page includes the following fields:
Object Description
 Port The switch port number of the logical port
 Forwarded Display the current forwarded
 Chaddr Check Dropped Display the chaddr check dropped
 Untrust Port Dropped Display untrust port dropped
 Untrust Port with
Option82 Dropped Display untrust port with option82 dropped
 Invaild Dropped Display invalid dropped
Buttons
: Click to clear the statistics.
: Click to refresh the statistics.
4.9.7.6 Database Agent
Overview of the DHCP Snooping Database Agent
When DHCP snooping is enabled, the switch uses the DHCP snooping binding database to store information about untrusted
interfaces. The database can have up to 8192 bindings.
Each database entry (binding) has an IP address, an associated MAC address, the lease time (in hexadecimal format), the
interface to which the binding applies, and the VLAN to which the interface belongs. A checksum value, the end of each entry, is
the number of bytes from the start of the file to end of the entry. Each entry is 72 bytes, followed by a space and then the
checksum value.
To keep the bindings when the switch reloads, you must use the DHCP snooping database agent. If the agent is disabled,
dynamic ARP or IP source guard is enabled, and the DHCP snooping binding database has dynamic bindings, the switch loses
its connectivity. If the agent is disabled and only DHCP snooping is enabled, the switch does not lose its connectivity, but DHCP
snooping might not prevent DCHP spoofing attacks.
The database agent stores the bindings in a file at a configured location. When reloading, the switch reads the binding file to
build the DHCP snooping binding database. The switch keeps the file current by updating it when the database changes.
When a switch learns of new bindings or when it loses bindings, the switch immediately updates the entries in the database.