CSIS330 Module 14 - IP Addressing Exam
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answer
CSIS330 Module 14 - IP Addressing Exam Study Guide | 1
,Question 1
How many bits must be borrowed from the host portion of an address to
accommodate a router with five connected networks?
☐ two
☐ four
☑ three
☐ five
Explanation: Three bits create 2^3 = 8 subnets. Two bits create only four, so three is the minimum that
supports five networks.
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Question 2
What is the usable number of host IP addresses on a network that has a /26 mask?
☐ 16
☐ 64
☐ 256
☐ 254
☑ 62
☐ 32
Explanation: A /26 leaves 6 host bits. That gives 2^6 = 64 total addresses; subtract the network and
broadcast addresses to get 62 usable hosts.
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CSIS330 Module 14 - IP Addressing Exam Study Guide | 2
, Question 3
A site administrator has been told that a particular network at the site must
accommodate 126 hosts. Which subnet mask would be used that contains the
required number of host bits?
☐ 255.255.255.0
☑ 255.255.255.128
☐ 255.255.255.240
☐ 255.255.255.224
Explanation: Seven host bits provide 2^7 - 2 = 126 usable addresses. A mask with seven host bits is /25, or
255.255.255.128.
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Question 4
A high school in New York (school A) is using videoconferencing technology to
establish student interactions with another high school (school B) in Russia. The
videoconferencing is conducted between two end devices through the Internet.
The network administrator of school A configures the end device with the IP
address 209.165.201.10. The administrator sends a request for the IP address for
the end device in school B and the response is 192.168.25.10. Neither school is
using a VPN. The administrator knows immediately that this IP will not work.
Why?
☐ This is a link-local address.
☐ This is a loopback address.
☐ There is an IP address conflict.
☑ This is a private IP address.
Explanation: 192.168.25.10 is in the private 192.168.0.0/16 range. Private addresses are not routed directly
across the public Internet without translation or a VPN.
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CSIS330 Module 14 - IP Addressing Exam Study Guide | 3
Green highlight = correct
answer
CSIS330 Module 14 - IP Addressing Exam Study Guide | 1
,Question 1
How many bits must be borrowed from the host portion of an address to
accommodate a router with five connected networks?
☐ two
☐ four
☑ three
☐ five
Explanation: Three bits create 2^3 = 8 subnets. Two bits create only four, so three is the minimum that
supports five networks.
———————————————————————————————————————————————————
————
Question 2
What is the usable number of host IP addresses on a network that has a /26 mask?
☐ 16
☐ 64
☐ 256
☐ 254
☑ 62
☐ 32
Explanation: A /26 leaves 6 host bits. That gives 2^6 = 64 total addresses; subtract the network and
broadcast addresses to get 62 usable hosts.
———————————————————————————————————————————————————
————
CSIS330 Module 14 - IP Addressing Exam Study Guide | 2
, Question 3
A site administrator has been told that a particular network at the site must
accommodate 126 hosts. Which subnet mask would be used that contains the
required number of host bits?
☐ 255.255.255.0
☑ 255.255.255.128
☐ 255.255.255.240
☐ 255.255.255.224
Explanation: Seven host bits provide 2^7 - 2 = 126 usable addresses. A mask with seven host bits is /25, or
255.255.255.128.
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————
Question 4
A high school in New York (school A) is using videoconferencing technology to
establish student interactions with another high school (school B) in Russia. The
videoconferencing is conducted between two end devices through the Internet.
The network administrator of school A configures the end device with the IP
address 209.165.201.10. The administrator sends a request for the IP address for
the end device in school B and the response is 192.168.25.10. Neither school is
using a VPN. The administrator knows immediately that this IP will not work.
Why?
☐ This is a link-local address.
☐ This is a loopback address.
☐ There is an IP address conflict.
☑ This is a private IP address.
Explanation: 192.168.25.10 is in the private 192.168.0.0/16 range. Private addresses are not routed directly
across the public Internet without translation or a VPN.
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CSIS330 Module 14 - IP Addressing Exam Study Guide | 3
