User Manual

24-Port and 48-Port Gigabit Ethernet PoE+ Smart Switches with 4 SFP Ports
Configure System Information User Manual132
7. Select whether to display physical interfaces, LAGs, or both by clicking one of the following
links above the table heading:
•1 (the unit ID of the switch). Only physical interfaces are displayed.
This is the default
setting.
•
LAG. Only LAGs are displayed.
• All. Both physical interfaces and LAGs are displayed.
8. Select one or more interfaces by taking one of the following actions:
• T
o configure a single interface, select the check box associated with the port, or type
the port number in the
Go To Interface field and click the Go button.
• To configure multiple interfaces with the same settings, select the check box
associated with each interface.
• To configure all interfaces with the same settings, select the check box in the heading
row
.
9. From the Trust Mode
menu, select the desired trust mode:
• Disabled. The interface is considered to be untrusted and could potentially be used to
launch a network attack. DHCP server messages are checked against the bindings
database. On untrusted ports, DHCP snooping enforces the following security rules:
- DHCP packets from a DHCP server (DHCPOFFER, DHCPACK, DHCPNAK,
DHCPRELEASEQUER
Y) are dropped.
- DHCPRELEASE and DHCPDECLINE messages are dropped if the MAC address
is in the snooping database but the binding’s interface is other than the interface
where the message was received.
- DHCP packets are dropped when the source MAC address does not match the
client hardware address if MAC address validation is globally enabled.
•
Enabled. The interface is considered to be trusted and forwards DHCP server
messages without validation.
10. From the Logging Invalid Packets menu,
select the packet logging mode.
When enabled, the DHCP snooping feature generates a log message when an invalid
packet is received and dropped by the interface.
11. In the Rate Limit (pps) field, specify the rate limit value for DHCP snooping purposes.
If the incoming rate of DHCP packets per second exceeds the configured burst interval
per second, the port shuts down. If the rate limit value is N/A, then the burst interval is
also nonapplicable, and rate limiting is disabled.