CCST IP Addressing & Subnetting 2 — Questions and Answers
Question 1: What is the subnet mask in CIDR notation for the address 192.168.10.0/26?
- 255.255.255.192 (Correct answer)
- 255.255.255.128
- 255.255.255.224
- 255.255.255.240
Correct answer: 255.255.255.192
/26 means 26 bits are set to 1, producing a subnet mask of 255.255.255.192.
Question 2: How many usable host addresses are available in a /29 subnet?
- 6 (Correct answer)
- 8
- 14
- 30
Correct answer: 6
A /29 subnet has 2^3 = 8 addresses total, minus 2 (network and broadcast) = 6 usable hosts.
Question 3: Which IP address class uses the default subnet mask 255.255.0.0?
- Class B (Correct answer)
- Class A
- Class C
- Class D
Correct answer: Class B
Class B addresses (128.0.0.0–191.255.255.255) use the default subnet mask 255.255.0.0.
Question 4: What is the broadcast address for the subnet 10.0.0.64/26?
- 10.0.0.127 (Correct answer)
- 10.0.0.128
- 10.0.0.126
- 10.0.0.255
Correct answer: 10.0.0.127
The /26 block starting at .64 spans .64–.127, so .127 is the broadcast address.
Question 5: A host has the IP address 172.16.50.100 with a /20 mask. What is the network address?
- 172.16.48.0 (Correct answer)
- 172.16.50.0
- 172.16.32.0
- 172.16.64.0
Correct answer: 172.16.48.0
/20 increments in blocks of 16 in the third octet; 48 is the nearest multiple of 16 below 50.
Question 6: Which of the following is a valid private IP address range as defined by RFC 1918?
- 172.16.0.0–172.31.255.255 (Correct answer)
- 172.0.0.0–172.15.255.255
- 192.168.0.0–192.168.0.255
- 10.0.0.0–10.255.255.0
Correct answer: 172.16.0.0–172.31.255.255
RFC 1918 defines 172.16.0.0/12, which spans 172.16.0.0 through 172.31.255.255.
Question 7: What type of IPv4 address is 169.254.10.5?
- APIPA (link-local) (Correct answer)
- Private
- Loopback
- Multicast
Correct answer: APIPA (link-local)
Addresses in the 169.254.0.0/16 range are APIPA (Automatic Private IP Addressing) link-local addresses assigned when DHCP fails.
CCST IP Addressing & Subnetting 2
What is the subnet mask in CIDR notation for the address 192.168.10.0/26?