Users Guide

Virtual Router Redundancy Protocol (VRRP)
Do not enable the DHCP client on an interface and set the priority to 255 or assign the same DHCP interface
IP address to a VRRP virtual group. Doing so guarantees that this router becomes the VRRP group owner.
To use the router as the VRRP owner, if you enable a DHCP client on an interface that is added to a VRRP
group, assign a priority less than 255 but higher than any other priority assigned in the group.
Configure the System for User Port
Stacking (Option 230)
Set the stacking-option variable to provide stack-port detail on the DHCP server when you set the DHCP
offer. A stack can be formed when the units are connected.
Option 230 is the option for user port stacking. Use it to create up to eight stack groups. Define the
configuration parameters on the DHCP server for each chassis based on the chassis MAC address. Configure
the following parameters:
• unit number
• priority
• stack group ID
The received stacking configuration is always applied on the master stack unit.
option #230 "unit-number:3#priority:2#stack-group:14"
Configure Secure DHCP
DHCP as defined by RFC 2131 provides no authentication or security mechanisms. Secure DHCP is a suite of
features that protects networks that use dynamic address allocation from spoofing and attacks.
• Option 82
• DHCP Snooping
• Dynamic ARP Inspection
• Source Address Validation
Option 82
RFC 3046 (the relay agent information option, or Option 82) is used for class-based IP address assignment.
The code for the relay agent information option is 82, and is comprised of two sub-options, circuit ID and
remote ID.
Circuit ID
This is the interface on which the client-originated message is received.
Dynamic Host Configuration Protocol (DHCP) 302