Chapter 26 IP Source Guard
GS1920v2 Series User’s Guide
245
The following table describes the labels in this screen.
26.6.2 DHC P Sno o ping VLAN C o nfig ure
Use this screen to enable DHCP snooping on each VLAN and to specify whether or not the Switch adds
DHCP relay agent option 82 information (
Chapter 37 on page 323
) to DHCP requests that the Switch
relays to a DHCP server for each VLAN. To open this screen, click
Adva nc e d Applic a tio n > IP So urc e
G ua rd > IPv4 So urc e G ua rd Se tup > DHC P Sno o ping > C o nfig ure > VLAN
.
Table 104 Advanced Application > IP Source Guard > IPv4 Source Guard Setup > DHCP Snooping >
Configure > Port
LABEL
DESC RIPTIO N
Port
This field displays the port number. If you configure the
*
port, the settings are applied
to all of the ports.
*
Settings in this row apply to all ports.
Use this row only if you want to make some settings the same for all ports. Use this row
first to set the common settings and then make adjustments on a port-by-port basis.
Note: Changes in this row are copied to all the ports as soon as you make
them.
Server Trusted state
Select whether this port is a trusted port (
Truste d
) or an untrusted port (
Untruste d
).
Trusted ports are connected to DHCP servers or other switches, and the Switch discards
DHCP packets from trusted ports only if the rate at which DHCP packets arrive is too
high.
Untrusted ports are connected to subscribers, and the Switch discards DHCP packets
from untrusted ports in the following situations:
•
The packet is a DHCP server packet (for example, OFFER, ACK, or NACK).
•
The source MAC address and source IP address in the packet do not match any of
the current bindings.
•
The packet is a RELEASE or DECLINE packet, and the source MAC address and
source port do not match any of the current bindings.
•
The rate at which DHCP packets arrive is too high.
Rate (pps)
Specify the maximum number for DHCP packets (1-2048) that the Switch receives from
each port each second. The Switch discards any additional DHCP packets. Enter 0 to
disable this limit, which is recommended for trusted ports.
Apply
Click
Apply
to save your changes to the Switch’s run-time memory. The Switch loses
these changes if it is turned off or loses power, so use the
Sa ve
link on the top
navigation panel to save your changes to the non-volatile memory when you are
done configuring.
Cancel
Click this to reset the values in this screen to their last-saved values.
