ZyXEL Communications GS2200 Series, Руководство пользователя

Страница: 196 / 320

Chapter 25 IP Source Guard
GS2200 Series User’s Guide
196
You can also specify the maximum number for DHCP packets that each port (trusted or untrusted)
can receive each second. To open this screen, click Advanced Application > IP Source Guard >
DHCP Snooping > Configure > Port.
Figure 124
DHCP Snooping Port Configure
The following table describes the labels in this screen.
Table 71
DHCP Snooping Port Configure
LABEL DESCRIPTION
Port This field displays the port number. If you configure the * port, the settings are
applied to all of the ports.
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 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.