CRT 8.4 Configure DHCPv6 Server

Which three DHCPv6 roles can a router perform? (Choose all that apply.) - DHCPv6 client - DHCPv6 relay agent - DHCPv6 server

- DHCPv6 client - DHCPv6 relay agent - DHCPv6 server

Which command is not configured in stateless DHCPv6? - address prefix ipv6-address/prefix - domain-name name - dns-server server-address - ipv6 dhcp server pool-name

- address prefix ipv6-address/prefix

An IPv6-enabled router is to acquire its IPv6 GUA from another IPv6 router using SLAAC. Which interface configuration command should be configured on the client router? - ipv6 address autoconfig - ipv6 address auto config - ipv6 address dhcp - ipv6 address dhcpv6

- ipv6 address autoconfig

Which command is configured on the client LAN interface of the DHCPv6 relay agent? - ip helper-address - ipv6 dhcp relay destination - ipv6 enable - ipv6 helper-address

- ipv6 dhcp relay destination

A router is to provide DHCPv6 server services. Which command should be configured on the client facing interface? - ipv6 enable - ipv6 dhcp pool POOL-NAME - ipv6 dhcp server POOL-NAME - ipv6 nd other-config-flag

- ipv6 dhcp server POOL-NAME

Which DHCPv6 verification command would display the link-local and GUA assigned address for each active client? - show ip dhcp pool - show ipv6 dhcp binding - show ipv6 dhcp interface - show ipv6 dhcp pool

- show ipv6 dhcp binding

The no ipv6 nd prefix default no-autoconfig command sets the _ flag back to its default of 1.

A

Router# show ipv6 dhcp interface

The DHCPv6 relay agent can be verified using the show ipv6 dhcp interface command.

Router# show ipv6 dhcp binding

Use the show ipv6 dhcp binding command output to display the IPv6 link-local address of the client and the global unicast address assigned by the server.

Router(config-dhcpv6)# address prefix

With stateful DHCPv6, all addressing and other configuration parameters must be assigned by the DHCPv6 server. The address prefix command is used to indicate the pool of addresses to be allocated by the server. Other information provided by the stateful DHCPv6 server typically includes DNS server address and the domain name.

An IPv6-enabled router is to acquire its IPv6 GUA from a DHCPv6 server. Which interface configuration command should be configured on client router? - ipv6 address autoconfig - ipv6 address auto config - ipv6 address dhcp - ipv6 address dhcpv6

- ipv6 address dhcp

A Cisco IOS router can be configured to provide DHCPv6 server services as 1 of 3 roles:

1) DHCPv6 Server 2) DHCPv6 Client 3) DHCPv6 Relay Agent

DHCPv6 Client

Router interface acquires an IPv6 IP configuration from a DHCPv6 server.

Router(config-if)# ipv6 nd managed-config-flag

The M flag is manually changed from 0 to 1 using the interface command ipv6 nd managed-config-flag.

Router(config-if)# ipv6 dhcp relay destination ipv6-address [interface-type interface-number]

The command syntax to configure a router as a DHCPv6 relay agent is as follows. This command is configured on the interface facing the DHCPv6 clients and specifies the DHCPv6 server address and egress interface to reach the server, as shown in the output. The egress interface is only required when the next-hop address is an LLA.

Router(config-if)# ipv6 address dhcp

The ipv6 address dhcp command configures a router to solicit its IPv6 addressing information from a DHCPv6 server.

Router(config-if)# ipv6 dhcp server POOL-NAME

The ipv6 dhcp server command binds the DHCPv6 pool to the interface. R1 will now respond with the information contained in the pool when it receives stateful DHCPv6 requests on this interface.

There are five steps to configure and verify a router as a stateful DHCPv6 client.

1) Enable IPv6 routing. 2) Configure the client router to create an LLA. 3) Configure the client router to use DHCPv6. 4) Verify that the client router is assigned a GUA. 5) Verify that the client router received other necessary DHCPv6 information.

There are five steps to configure and verify a router as a stateless DHCPv6 client.

1) Enable IPv6 routing. 2) Configure the client router to create an LLA. 3) Configure the client router to use SLAAC. 4) Verify that the client router is assigned a GUA. 5) Verify that the client router received other necessary DHCPv6 information.

There are five steps to configure and verify a router as a stateless DHCPv6 server:

1) Enable IPv6 routing. 2) Define a DHCPv6 pool name 3) Configure the DHCPv6 pool. 4) Bind the DHCPv6 pool to an interface. 5) Verify that the hosts have received IPv6 addressing information.

There are five steps to configure and verify a router as a stateful DHCPv6 server:

1) Enable IPv6 routing. 2) Define a DHCPv6 pool name. 3) Configure the DHCPv6 pool. 4) Bind the DHCPv6 pool to an interface. 5) Verify that the hosts have received IPv6 addressing information.

Router(config)# ipv6 dhcp pool POOL-NAME

Create the DHCPv6 pool using the ipv6 dhcp pool POOL-NAME global config command. This enters DHCPv6 pool sub-configuration mode as identified by the Router(config-dhcpv6)# prompt.

You can use the no ipv6 nd managed-config-flag command to set the _ flag back to its default of 0.

M

DHCPv6 Relay Agent

Router provides DHCPv6 forwarding services when the client and the server are located on different networks.

DHCPv6 Server

Router provides stateless or stateful DHCPv6 services.

When a router is providing [STATELESS / STATEFUL] DHCPv6 services, it also maintains a database of assigned IPv6 addresses.

STATEFUL

Router(config-if)# ipv6 nd prefix default no-autoconfig

The A flag is manually changed from 1 to 0 using the interface command ipv6 nd prefix default no-autoconfig. The A flag can be left at 1, but some client operating systems such as Windows will create a GUA using SLAAC and get a GUA from the stateful DHCPv6 server. Setting the A flag to 0 tells the client not to use SLAAC to create a GUA.

Router(config-if)# ipv6 dhcp server POOL-NAME

The DHCPv6 pool has to be bound to the interface using the ipv6 dhcp server POOL-NAME interface config command as shown in the output.

Router(config-if)# ipv6 address autoconfig

The client router needs to be configured to use SLAAC to create an IPv6 configuration. The ipv6 address autoconfig command enables the automatic configuration of IPv6 addressing using SLAAC.

Router(config-if)# ipv6 enable

The client router needs to have a link-local address. An IPv6 link-local address is created on a router interface when a global unicast address is configured. It can also be created without a GUA using the ipv6 enable interface configuration command. Cisco IOS uses EUI-64 to create a randomized Interface ID.

Router(config)# ipv6 unicast-routing

The ipv6 unicast-routing command is required to enable IPv6 routing. Although it is not necessary for the router to be a stateless DHCPv6 server, it is required for the router to source ICMPv6 RA messages.

Router(config-if)# ipv6 nd other-config-flag

The router responds to stateless DHCPv6 requests on this interface with the information contained in the pool. The O flag needs to be manually changed from 0 to 1 using the interface command ipv6 nd other-config-flag. RA messages sent on this interface indicate that additional information is available from a stateless DHCPv6 server. The A flag is 1 by default, telling clients to use SLAAC to create their own GUA.

Router# show ipv6 dhcp pool

The show ipv6 dhcp pool command verifies the name of the DHCPv6 pool and its parameters. The command also identifies the number of active clients. In this example, the IPV6-STATEFUL pool currently has 2 clients, which reflects PC1 and R3 receiving their IPv6 global unicast address from this server.

Router# show ipv6 dhcp binding command

Use the show ipv6 dhcp binding command to verify if any hosts have been assigned an IPv6 configuration.