ZyXEL Communications OLT2406, Руководство пользователя

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Chapter 27 IP Source Guard
OLT2406 User’s Guide
233
The following table describes the labels in this screen.
27.5.2 DHCP Snooping VLAN Configure
Use this screen to enable DHCP snooping on each VLAN and to specify whether or not the OLT adds
DHCP relay agent option 82 information (
Chapter 42 on page 332 ) to DHCP requests that the OLT relays
to a DHCP server for each VLAN. To open this screen, click Advanced Application > IP Source Guard >
DHCP Snooping > Configure > VLAN .
See Section 27.10.1.4 on page 243 for more information about the configuration order for DHCP option
82 settings in different screens.
Table 85 Advanced Application > IP Source Guard > IPv4 Source Guard Setup > DHCP Snooping >
Configure > Port
LABEL DESCRIPTION
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 ( Trusted ) or an untrusted port ( Untrusted ).
Trusted ports are connected to DHCP servers or other switches, and the OLT 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 OLT 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 OLT receives from
each port each second. The OLT 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 OLT’s run-time memory. The OLT loses these
changes if it is turned off or loses power, so use the Save 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.