Cisco CCNA IPv4 and IPv6 Addressing 2 — Questions and Answers
Question 1: Which IPv4 address class supports the most hosts per network?
- Class A (Correct answer)
- Class B
- Class C
- 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 2: What is the subnet mask for a /26 prefix length in dotted-decimal notation?
- 255.255.255.128
- 255.255.255.192 (Correct answer)
- 255.255.255.224
- 255.255.255.240
Correct answer: 255.255.255.192
A /26 mask has 26 consecutive 1-bits, giving 255.255.255.192 (11000000 in the last octet).
Question 3: An IPv6 address written as 2001:0DB8:0000:0000:0000:0000:0000:0001 can be abbreviated to which of the following?
- 2001:DB8::1 (Correct answer)
- 2001:DB8:0::1
- 2001:DB8:::1
- 2001:0DB8::0001
Correct answer: 2001:DB8::1
Leading zeros in each group can be removed and consecutive all-zero groups replaced with :: once, yielding 2001:DB8::1.
Question 4: Which command verifies the IPv6 address configured on a Cisco router interface?
- show ip interface brief
- show ipv6 interface brief (Correct answer)
- show version
- show ip route
Correct answer: show ipv6 interface brief
The 'show ipv6 interface brief' command displays IPv6 addresses and status for all interfaces.
Question 5: 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 – 192.168.10.127
- 192.168.10.64 – 192.168.10.126
Correct answer: 192.168.10.65 – 192.168.10.126
The network address is .64 and the broadcast is .127, so valid hosts are .65 through .126.
Question 6: Which IPv6 address type is equivalent to an IPv4 private address and is used only within a site?
- Global unicast
- Link-local
- Unique local (Correct answer)
- Multicast
Correct answer: Unique local
Unique local addresses (FC00::/7) are used for internal communication within a site, similar to RFC 1918 private IPv4 addresses.
Question 7: A network administrator needs to divide 172.16.0.0/16 into subnets each supporting at least 500 hosts. Which subnet mask should be used?
- /23 (Correct answer)
- /24
- /22
- /25
Correct answer: /23
A /23 mask leaves 9 host bits (2^9 – 2 = 510 usable hosts), which satisfies the requirement of at least 500 hosts.
Cisco CCNA IPv4 and IPv6 Addressing 2
Which IPv4 address class supports the most hosts per network?