Network Security Test on “Classless Addressing”.
1. Classless Addressing overcomes the problem of –
a) address completion
b) address depletion
c) address extraction
d) all of the mentioned
Answer: b
Clarification: Classless Addressing overcomes the problem of address depletion.
2. Which of the following is true for classless addressing?
a) The addresses are contiguous
b) The number of addresses is a power of 2 (16 = 24), and the first address is divisible by 16
c) The first address, when converted to a decimal number, is 3,440,387,360, which when divided by 16 results in 215,024,210
d) All of the mentioned
Answer: d
Clarification: All the statements are true.
3. The value ‘n’ in classless addressing is referred to as –
a) prefix length
b) suffix length
c) intermediate length
d) none of the mentioned
Answer: a
Clarification: ‘n’ is referred to as prefix length.
4. Which of the following values can ‘n’ not take?
a) 16
b) 8
c) 20
d) 24
Answer: c
Clarification: ‘n’ can only have values 8, 16, or 24.
5. The slash notation in classless addressing is referred to as –
a) NIFT
b) PITF
c) CIDR
d) TRS
Answer: c
Clarification: It is referred to as CIDR.
6. CIDR stands for –
a) Class In Domain Range
b) Classless Inter Domain Routing
c) Classless In Domain Range
d) None of the mentioned.
Answer: b
Clarification: CIDR stands for Classless Inter Domain Routing.
7. A classless address is given as 167.199.170.82/27. Find the number of addresses.
a) 128
b) 64
c) 32
d) 16
Answer: c
Clarification: n =27
Therefore number of addresses is 2(32-n) = 32.
8. A classless address is given as 167.199.170.82/27. Find the first address.
a) 167.199.170.32
b) 167.199.170.82
c) 167.199.170.64
d) 167.199.170.78
Answer: c
Clarification: First address = (any address) AND (network mask).
9. A classless address is given as 167.199.170.82/27. Find the last address.
a) 167.199.170.95
b) 167.199.170.256
c) 167.199.170.128
d) 167.199.170.88
Answer: a
Clarification: Last address = (any address) OR [NOT (network mask)].
10. No. of address in the block= N= NOT(mask)+1.
a) True
b) False
Answer: a
Clarification: The statement is true.
11. ICANN stands for Internet Corporation for Assigned Names and Addresses.
a) True
b) False
Answer: a
Clarification: The address block allocation is managed by a global authority called the ICANN.
12. An ISP has requested a block of 1000 addresses. How many blocks are granted to it?
a) 512
b) 1000
c) 1024
d) None of the mentioned
Answer: c
Clarification: The number of blocks allotted can only be in the powers of 2.
13. An ISP has requested a block of 1000 addresses. What is its prefix length?
a) 28
b) 22
c) 26
d) 24
Answer: b
Clarification: n =32- log_2 (1024) = 22.
14. An ISP has requested a block of 1000 addresses. Can 18.14.12.0 be its first address?
a) Yes
b) No
c) Can’t Say
d) Insufficient Data
Answer: a
Clarification: 18.14.12.0 is divisible by 1024 hence it can be taken as first address.
15. If the first address is First address = 18.14.12.0/22. What is the last address?
a) 18.14.15.128/22
b) 18.14.15.64/22
c) 18.14.15.32/22
d) 18.14.15.255/22
Answer: d
Clarification: Last address = (any address) OR [NOT (network mask)].
The Last Address = 18.14.15.255/22.