Module chapter 8
Which destination IP address is used when an IPv6 host sends a DHCPv6 SOLICIT message to locate a DHCPv6 server?
FF02::2 DHCPv6 hosts will send a DHCP SOLICIT message to the all DHCP routers multicast address of FF02::2.
What process is used in ICMPv6 for a host to verify that an IPv6 address is unique before configuring it on an interface?
DAD Before an IPv6 host can enable and use an assigned IPv6 address, the host must verify that the address is unique on the network. To verify that no other hosts are using the IPv6 address, the host performs the duplicate address detection (DAD) process by sending a Neighbor Solicitation (NS) message to the IPv6 address.
A company implements the stateless DHCPv6 method for configuring IPv6 addresses on employee workstations. After a workstation receives messages from multiple DHCPv6 servers to indicate their availability for DHCPv6 service, which message does it send to a server for configuration information?
DHCPv6 INFORMATION-REQUEST In stateless DHCPv6 configuration, a client configures its IPv6 address by using the prefix and prefix length in the RA message, combined with a self-generated interface ID. It then contacts a DHCPv6 server for additional configuration information via an INFORMATION-REQUEST message. The DHCPv6 SOLICIT message is used by a client to locate a DHCPv6 server. The DHCPv6 ADVERTISE message is used by DHCPv6 servers to indicate their availability for DHCPv6 service. The DHCPv6 REQUEST message is used by a client, in the stateful DHCPv6 configuration, to request ALL configuration information from a DHCPv6 server.
Which three DHCPv6 roles can a router perform?
DHCPv6 client DHCPv6 relay agent DHCPv6 server
A network administrator is entering the command ipv6 unicast-routing to start configuring DHCPv6 operation on a router. Which statement describes the function of this command?
It is required for sending ICMPv6 RA messages. The ipv6 unicast-routing command is required to enable IPv6 routing on a router. This command is not necessary for the router to be a stateless or stateful DHCPv6 server, but is required for sending ICMPv6 RA messages.
A client is using SLAAC to obtain an IPv6 address for its interface. After an address has been generated and applied to the interface, what must the client do before it can begin to use this IPv6 address?
It must send an ICMPv6 Neighbor Soliciation message to ensure that the address is not already in use on the network. Stateless DHCPv6 or stateful DHCPv6 uses a DHCP server, but Stateless Address Autoconfiguration (SLAAC) does not. A SLAAC client can automatically generate an address that is based on information from local routers via Router Advertisement (RA) messages. Once an address has been assigned to an interface via SLAAC, the client must ensure via Duplicate Address Detection (DAD) that the address is not already in use. It does this by sending out an ICMPv6 Neighbor Solicitation message and listening for a response. If a response is received, then it means that another device is already using this address.
How does an IPv6 client ensure that it has a unique address after it configures its IPv6 address using the SLAAC allocation method?
It sends an ICMPv6 Neighbor Solicitation messsage with the IPv6 address as the target IPv6 ddress. SLAAC is a stateless allocation method and does not use a DHCP server to manage the IPv6 addresses. When a host generates an IPv6 address, it must verify that it is unique. The host will send an ICMPv6 Neighbor Solicitation message with its own IPv6 address as the target. As long as no other device responds with a Neighbor Advertisement message, then the address is unique.
In which alternative to DHCPv6 does a router dynamically provide IPv6 configuration information to hosts?
SLAAC Stateless Address Autoconfiguration (SLAAC) can be used as an alternative to DHCPv6. In this approach, a router provides global routing prefix, prefix length, default gateway, and DNS server information to a host. The host is not provided with a global unicast address by SLAAC. Instead, SLAAC suggests that the host create its own global unicast address based on the supplied global routing prefix. ARP is not used in IPv6. ICMPv6 messages are used by SLAAC to provide addressing and other configuration information. EUI-64 is a process in which a host will create an Interface ID from its 48-bit MAC address.
After booting, a client receives an ICMPv6 RA message with the M flag set to 0 and the O flag set to 1. What does this indicate?
The client should automatically configure an IPv6 address and then contact a DHCPv6 server for more information. The Managed Address Configuration (M) flag and the Other Configuration (O) flag in ICMPv6 RA messages are used to indicate to an IPv6 client how it should configure its IPv6 addresses. If the M flag is set to 0 it means that the host should automatically configure its own IPv6 interface address rather than asking for one from a DHCPv6 server. If the O flag is set to 1, it means that the client can find additional addressing information, such as a DNS server address, by contacting a DHCPv6 server after it has automatically configured its own address.
What are two characteristics of the SLAAC method for IPv6 address configuration?
The default gateway of an IPv6 client on a LAN will be the link-local address of the router interface attached to the LAN. IPv6 addressing is dynamically assigned to clients through the use of IMCPv6. With SLAAC, the default gateway for IPv6 clients will be the link-local address of the router interface that is attached to the client LAN. The IPv6 addressing is dynamically assigned via the ICMPv6 protocol. SLAAC is a stateless method of acquiring an IPv6 address, a method that requires no servers. When a client is configured to obtain its addressing information automatically via SLAAC, the client sends a router solicitation message to the IPv6 all-routers multicast address FF02::2. The router advertisement messages are sent by routers to provide addressing information to clients.
What does the ipv6 address autoconfigure command do?
The ipv6 address autoconfigure command tells the router to use either SLAAC or stateless DHCPv6 to configure its global unicast address.
What does the ipv6 dhcp server command do?
The ipv6 dhcp server command is used on a router that is running a DHCPv6 server to indicate what address information should be served to clients.
Which command is not configured in stateless DHCPv6?
address prefix ipv6-address/prefix Used for stateful DHCPv6.
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 Command configured a router interface to be a DHCPv6 client.
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 dhcp Command is configured a router interface to be a DHCPv6 client
Which command should be configured on a router interface to set the router as a stateful DHCPv6 client?
ipv6 address dhcp When the ipv6 address dhcp command is configured on a router interface, it enables the router as a DHCPv6 client on this interface.
Which command is configured on the client LAN interface of the DHCPv6 relay agent?
ipv6 dhcp relay destination issued on the client facing interfgace of the DHCPv6 relay agent.
A router is to provide DHCPv6 server services. Which command should be configured on the client facing interface?
ipv6 dhcp server POOL-NAME Command is issued on the router interface facing the DHCPv6 clients.
What two methods can be used to generate an interface ID by an IPv6 host that is using SLAAC?
random generation EUI-64 A host that is using SLAAC has two means to configure an interface ID: EUI-64 and random generation by the host operating system.
Which method would an IPv6-enabled host using SLAAC employ to learn the address of the default gateway?
router advertisements that are received from the link router. When using SLAAC, a host will learn from the router advertisement that is sent by the link router the address to use as a default gateway.
Which DHCPv6 verification command would display the link-local and GUA assigned address for each active client?
show ipv6 dhcp binding command output will show active DHCPv6 leases to clients.
What message informs IPv6 enabled interfaces to use stateful DHCPv6 for obtaining an IPv6 address?
the ICMPv6 Router Advertisement Before an IPv6 enabled interface will use stateful DHCPv6 to obtain an IPv6 address, the interface must receive an ICMPv6 Router Advertisement with the managed configuration flag (M flag) set to 1.
