Chapter 9
  |  General Security Measures
DHCPv6 Snooping
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If an incoming packet is a DHCPv6 request packet with option 37 
information, it will modify the option 37 information according to settings 
specified with ipv6 dhcp snooping option remote-id policy command. 
■
If an incoming packet is a DHCPv6 request packet without option 37 
information, enabling the DHCPv6 snooping information option will add 
option 37 information to the packet. 
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If an incoming packet is a DHCPv6 reply packet with option 37 information, 
enabling the DHCPv6 snooping information option will remove option 37 
information from the packet. 
◆ When this switch inserts Option 37 information in DHCPv6 client request 
packets, the switch’s MAC address (hexadecimal) is used for the remote ID. 
Example
This example enables the DHCPv6 Snooping Remote-ID Option. 
Console(config)#ipv6 dhcp snooping option remote-id
Console(config)#
ipv6 dhcp snooping
option remote-id
policy
This command sets the remote-id option policy for DHCPv6 client packets that 
include Option 37 information. Use the no form to disable this function.
Syntax 
ipv6 dhcp snooping option remote-id policy {drop | keep | replace}
no ipv6 dhcp snooping option remote-id policy
drop - Drops the client’s request packet instead of relaying it.
keep - Retains the Option 37 information in the client request, and 
forwards the packets to trusted ports.
replace - Replaces the Option 37 remote-ID in the client’s request with the 
relay agent’s remote-ID (when DHCPv6 snooping is enabled), and forwards 
the packets to trusted ports.
Default Setting 
drop
Command Mode
Global Configuration
Command Usage
When the switch receives DHCPv6 packets from clients that already include DHCP 
Option 37 information, the switch can be configured to set the action policy for 
these packets. The switch can either drop the DHCPv6 packets, keep the existing 
information, or replace it with the switch’s relay agent information.