ICND1 IPv4 and IPv6 2 — Questions and Answers
Question 1: Which IPv6 address type is automatically assigned to every IPv6-enabled interface and is only valid on the local link?
- Global unicast
- Link-local (Correct answer)
- Multicast
- Anycast
Correct answer: Link-local
Link-local addresses (FE80::/10) are automatically configured on every IPv6 interface and are only routable on the local link.
Question 2: What is the valid host range for the subnet 192.168.10.64/26?
- 192.168.10.65 – 192.168.10.126 (Correct answer)
- 192.168.10.64 – 192.168.10.127
- 192.168.10.65 – 192.168.10.128
- 192.168.10.64 – 192.168.10.126
Correct answer: 192.168.10.65 – 192.168.10.126
A /26 has 64 addresses; network=.64, broadcast=.127, so valid hosts are .65 through .126.
Question 3: Which mechanism allows an IPv6 host to automatically generate its interface ID from its 48-bit MAC address?
- DHCPv6 stateful
- SLAAC with EUI-64 (Correct answer)
- IPv6 anycast
- 6to4 tunneling
Correct answer: SLAAC with EUI-64
EUI-64 inserts FFFE in the middle of the MAC address and flips the universal/local bit to form a 64-bit interface ID used with SLAAC.
Question 4: A packet is destined for 172.16.5.200. Which subnet does this address belong to if the mask is 255.255.255.192?
- 172.16.5.128/26
- 172.16.5.192/26 (Correct answer)
- 172.16.5.128/25
- 172.16.5.160/27
Correct answer: 172.16.5.192/26
/26 (255.255.255.192) creates blocks of 64: .0, .64, .128, .192; address .200 falls in the .192 subnet.
Question 5: Which IPv4 address class supports the most hosts per network?
- Class B
- Class C
- Class A (Correct answer)
- Class D
Correct answer: Class A
Class A networks use only 8 bits for the network portion, leaving 24 bits for hosts — supporting over 16 million hosts per network.
Question 6: What does the IPv6 prefix FF02::1 represent?
- All routers on the local link
- All nodes on the local link (Correct answer)
- Loopback address
- Solicited-node multicast
Correct answer: All nodes on the local link
FF02::1 is the all-nodes multicast address used to reach every IPv6-enabled device on the local link.
Question 7: How many usable host addresses are available in a /29 subnet?
- 6 (Correct answer)
- 8
- 14
- 30
Correct answer: 6
A /29 has 8 total addresses (2^3); subtracting the network and broadcast addresses leaves 6 usable host addresses.
ICND1 IPv4 and IPv6 2
Which IPv6 address type is automatically assigned to every IPv6-enabled interface and is only valid on the local link?