Chapter 26 IP Source Guard

The following table describes the labels in this screen.

Table 81 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

Select whether this port is a trusted port (Trusted) or an untrusted

state

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.

 

 

26.5.2 DHCP Snooping VLAN Configure

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 41 on page 361) to DHCP requests that the Switch relays to a DHCP server for each VLAN. To

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XGS-4526/4528F/4728F User’s Guide