CLI Reference Guide-R01

Chapter 29 | DHCP Commands
DHCP Relay
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enables DHCPv6 relay service for the VLAN from which the command is
entered.
◆ Up to five destination addresses may be defined using consecutive commands.
◆ This command is used to configure DHCPv6 relay functions for host devices
attached to the switch. If DHCPv6 relay service is enabled (by entering this
command), and this switch sees a DHCPv6 request broadcast, it inserts its own
IP address into the request so the DHCPv6 server will know the subnet where
the client is located. Then, the switch forwards the packet to the next relay
agent or DHCPv6 server on another network. When the server receives the
DHCPv6 request, it allocates a free IP address for the DHCPv6 client from its
defined scope for the DHCPv6 client’s subnet, and sends a DHCPv6 response
back to the DHCPv6 relay agent (i.e., this switch). This switch then broadcasts
the DHCPv6 response received from the server to the client.
◆ When the multicast option is used, the switch multicasts the modified client
request to all configured VLANs or to a specified VLAN, and enables DHCPv6
relay service for those VLANs.
◆ Up to five relay destinations may be configured by repeating this command.
◆ When issuing the no ipv6 dhcp relay destination command without any
arguments, the switch will delete all configured destination addresses and
disable DHCP for IPv6 relay for all VLANs.
EXAMPLE
Console(config)#interface vlan 1
Console(config-if)#ipv6 dhcp relay destination 2001:0DB8:3000:3000::42
Console(config-if)#
show ipv6 dhcp relay
destination
This command shows the destination addresses or VLAN to which client messages
are forwarded for DHCP relay service.
Syntax
show ipv6 dhcp relay destination interface [vlan vlan-id]
vlan-id - VLAN ID (Range: 1-4094)
Command Mode
Privileged Exec
Example
Console#show ipv6 dhcp relay destination interface vlan 1
DHCP relay destination :
VLAN 1 :