ZyXEL Communications GS-4012 - Manual (Page 210)

Chapter 24 IP Source Guard
GS-4012F/4024 User’s Guide
210
Figure 104 DHCP Snooping Port Configure
The following table describes the labels in this screen.
Table 72 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.
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
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.