Setup Guide

Congure 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 oer. 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. Dene the conguration parameters on the DHCP
server for each chassis based on the chassis MAC address. Congure the following parameters:
• unit number
• priority
• stack group ID
The received stacking conguration is always applied on the master stack unit.
option #230 "unit-number:3#priority:2#stack-group:14"
Congure Secure DHCP
DHCP as dened 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 spoong and attacks.
• Option 82
• DHCP Snooping
• Dynamic ARP Inspection
• Source Address Validation
Option 82 (DHCPv4 relay options)
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.
Remote ID This identies the host from which the message is received. The value of this sub-option is the MAC address of
the relay agent that adds Option 82.
In DHCPv4 relay , the Option 82 is not added by default. When the ip dhcp relay information-option is congured, the Option
82 with sub-options 1 (Agent Circuit ID) and 2 ( Agent Remote ID) are added to the relayed DHCP packet. The default values of the sub-
options are as follows:
• Default Agent Circuit ID is constructed in the format VLANID:LagID:SlotID:PortStr. When the port is fanned-out, the
PortStr is represented as mainPort:subPort.
• Default Agent Remote ID is the system MAC address (in binary format)
The following example shows the format of the Circuit ID - 723:0:1:1
Table 17. Circuit ID Format
VLAN ID LAG ID Slot ID Port Str
723 0 1 1
The DHCP relay agent inserts Option 82 before forwarding DHCP packets to the server. The server can use this information to:
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Dynamic Host Conguration Protocol (DHCP)