Cisco Catalyst 4500 Series Configuration Manual page 425

Chapter 2
Usage Guidelines The ipv6 dhcp relay destination command specifies a destination address to which client messages are
forwarded, and it enables DHCPv6 relay service on the interface. When relay service is enabled on an
interface, a DHCPv6 message received on that interface is forwarded to all configured relay destinations.
The incoming DHCPv6 message may have come from a client on that interface, or relayed by another
relay agent.
The relay destination can be a unicast address of a server or another relay agent, or it may be a multicast
address. There are two types of relay destination addresses:
•
•
If no output interface is configured for a destination, the output interface is determined by routing tables.
In this case, it is recommended that a unicast or multicast routing protocol be running on the device.
Multiple destinations can be configured on one interface, and multiple output interfaces can be
configured for one destination. When the relay agent relays messages to a multicast address, it sets the
hop limit field in the IPv6 packet header to 32.
Unspecified, loopback, and node-local multicast addresses are not acceptable as the relay destination. If
any one of them is configured, the message "Invalid destination address" is displayed.
Note that it is not necessary to enable the relay function on an interface for it to accept and forward an
incoming relay reply message from servers. By default, the relay function is disabled, and there is no
relay destination on an interface. The no form of the command removes a relay destination on an
interface or deletes an output interface for a destination. If all relay destinations are removed, the relay
service is disabled on the interface.
The DHCPv6 client, server, and relay functions are mutually exclusive on an interface. When one of
these functions is already enabled, and a user tries to configure a different function on the same interface,
one of the following messages is displayed: "Interface is in DHCP client mode," "Interface is in DHCP
server mode," or "Interface is in DHCP relay mode."
Examples The following example sets the relay destination address on Ethernet interface 4/3:
Device# configure terminal
Device(config)# interface gigabitethernet 0/0
Device(config-if)# ipv6 dhcp relay destination FE80::250:A2FF:FEBF:A056
gigabitethernet 4/3
Related Commands Command
interface
ipv6 dhcp-ldra
A link-scoped unicast or multicast IPv6 address, for which a user must specify an output interface
A global or site-scoped unicast or multicast IPv6 address. A user can optionally specify an output
interface for this kind of address.
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release XE 3.9.xE and 15.2(5)Ex
Description
Configures an interface and enters interface configuration
mode.
Enables LDRA functionality on an access node.
ipv6 dhcp relay destination
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