Test 5 - CCNA 2

How does an IPv6 client ensure that it has a unique address after it configures its IPv6 address using the SLAAC allocation method?

• It contacts the DHCPv6 server via a special formed ICMPv6 message.

• It checks with the IPv6 address database that is hosted by the SLAAC server.

• It sends an ARP message with the IPv6 address as the destination IPv6 address.

• It sends an ICMPv6 Neighbor Solicitation message with the IPv6 address as the target IPv6 address.

Answer explanation

Explanation: 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.

What two methods can be used to generate an interface ID by an IPv6 host that is using SLAAC? (Choose two.)

• random generation

• DAD

• stateful DHCPv6

• EUI-64

• ARP

Answer explanation

Explanation: 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 command should be configured on a router interface to set the router as a stateful DHCPv6 client?

• ipv6 enable

• ipv6 address dhcp

• ipv6 dhcp server stateful

• ipv6 address autoconfigure

What message informs IPv6 enabled interfaces to use stateful DHCPv6 for obtaining an IPv6 address?

• the ICMPv6 Router Advertisement

• the DHCPv6 Reply message

• the ICMPv6 Router Solicitation

• the DHCPv6 Advertise message

Answer explanation

Explanation: 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.

In which alternative to DHCPv6 does a router dynamically provide IPv6 configuration information to hosts?

Answer explanation

Explanation: 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.

What process is used in ICMPv6 for a host to verify that an IPv6 address is unique before configuring it on an interface?

Answer explanation

Explanation: 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.

An organization requires that LAN clients generate their IPv6 configuration using SLAAC. You have configured the IPv6 GUA on the router LAN interface and verified that the interface is UP. However, hosts are not generating an IPv6 GUA. Which other command should be configured to enable SLAAC?

• R1(config)# ipv6 dhcp pool pool-name

• R1(config)# ipv6 unicast-routing

• R1(config-if)# ipv6 enable

• R1(config-if)# ipv6 nd other-config-flag

Answer explanation

Explanation: For a router to be able to send RA messages, it must be enabled as an IPv6 router using the ipv6 unicast-routing global config command.

What is the purpose of HSRP?

• It prevents a rogue switch from becoming the STP root.

• It provides a continuous network connection when a router fails.

• It enables an access port to immediately transition to the forwarding state.

• It prevents malicious hosts from connecting to trunk ports.

Answer explanation

Explanation: HSRP is a first hop redundancy protocol and allows hosts to use multiple gateways through the use of a single virtual router.

Which nonproprietary protocol provides router redundancy for a group of routers which support IPv4 LANs?

• SLB

• HSRP

• VRRPv2

• GLBP

Answer explanation

Explanation: The only nonproprietary FHRP used for router redundancy listed in the options is VRRPv2. HSRP and GLBP are both Cisco proprietary FHRPs. IOS SLB is a Cisco-based solution used to load balance traffic across multiple servers.

When first hop redundancy protocols are used, which two items will be shared by a set of routers that are presenting the illusion of being a single router? (Choose two.)

• IP address

• BID

• hostname

• MAC address

• static route

Answer explanation

Explanation: In order for a set of routers to present the illusion of being a single router, they must share both an IP address and MAC address. A static route, BID, or hostname does not have to be shared in this context.