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Subnetting and Creating Custom Subnet Masks Practice Problems

 

Problem answers assume Non-RFC 1812 networks (must subtract 2 from the number of Host IDs).

 

Specify The Correct Default Subnet Mask for the Following Addresses:

Review:  Default Subnet Masks

 

Recommended Process

Determine address class of address.

            Determine appropriate default subnet mask.

 

210.23.67.102

66.23.148.0

158.23.251.33

144.23.117.254

192.254.23.123

144.207.78.1

63.125.23.211

192.25.128.36

128.12.254.98

134.223.156.89

127.0.0.1

224.23.108.23

223.78.27.144

77.123.28.167

191.249.222.234

 

(c) 1999 - 2001 Charles Botsford

Classroom use requires purchased license, see license agreement.

 

Determine the Appropriate Custom Subnet Masks:

Review:  Subnetting and Custom Subnet Masks

 

Recommended Process

Determine address class of address.

            First determine appropriate default subnet mask.

            Second determine the appropriate custom subnet mask that provides:

                        Subnets >= Physical Segments

                        Host IDs >= Hosts per Physical Segment

 

Example

Scenario 1

 

Required Number of Physical Segments:

5

Maximum Number of Hosts/Physical Segment:

5000

Network Address:

152.77.0.0

 

 

Proposed Custom Subnet Mask:

255.255.224.0

Number of Subnets Supported:

6

Maximum Number of Host ID per Subnet:

8190

 

 

Scenario 2

 

Required Number of Physical Segments:

100

Maximum Number of Hosts/Physical Segment:

88,000

Network Address:

39.0.0.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

Scenario 3

 

Required Number of Physical Segments:

100

Maximum Number of Hosts/Physical Segment:

350

Network Address:

177.133.0.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

Scenario 4

 

Required Number of Physical Segments:

4

Maximum Number of Hosts/Physical Segment:

1,500,000

Network Address:

120.0.0.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

(c) 1999 - 2001 Charles Botsford

Classroom use requires purchased license, see license agreement.

 

Scenario 5

 

Required Number of Physical Segments:

16

Maximum Number of Hosts/Physical Segment:

1,500

Network Address:

128.199.0.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

Scenario 6

 

Required Number of Physical Segments:

250

Maximum Number of Hosts/Physical Segment:

100

Network Address:

191.254.0.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

Scenario 7

 

Required Number of Physical Segments:

12

Maximum Number of Hosts/Physical Segment:

12

Network Address:

216.122.44.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

Scenario 8

 

Required Number of Physical Segments:

10

Maximum Number of Hosts/Physical Segment:

750,000

Network Address:

12.0.0.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

Scenario 9

 

Required Number of Physical Segments:

50

Maximum Number of Hosts/Physical Segment:

600

Network Address:

134.119.0.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

Scenario 10

 

Required Number of Physical Segments:

5

Maximum Number of Hosts/Physical Segment:

25

Network Address:

192.177.4.0

 

 

Proposed Custom Subnet Mask:

 

Number of Subnets Supported:

 

Maximum Number of Host ID per Subnet:

 

 

(c) 1999 - 2001 Charles Botsford

Classroom use requires purchased license, see license agreement.

 

Determine Subnet IDs and Ranges of Host IDs

Review:  Subnetting and Custom Subnet Masks

 

Recommended Process

Determine address class of address.

            First determine appropriate default subnet mask.

            Second determine the appropriate custom subnet mask that provides:

                        Subnets >= Physical Segments

                        Host IDs >= Hosts per Physical Segment

            Determine the Subnet IDs

            Determine the ranges of Host IDs

 

Example

 

Scenario 1

 

 

Number of Physical Segments:

5

 

Maximum Number of Hosts/Physical Segment:

5000

 

Network Address:

152.77.0.0

 

 

 

 

Proposed Custom Subnet Mask:

255.255.224.0

 

Number of Subnets Supported:

6

 

Maximum Number of Host ID per Subnet:

8190

 

Subnet IDs:

152.77.0.0  (Invalid)

152.77.32.0

152.77.64.0

152.77.96.0

152.77.128.0

152.77.160.0

152.77.192.0 

152.77.224.0  (Invalid)

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

152.77.32.0

152.77.64.0

152.77.96.0

152.77.128.0

152.77.160.0

152.77.191.0

152.77.32.1 – 152.77.63.254

152.77.64.1 – 152.77.95.254

152.77.96.1 – 152.77.127.254

152.77.128.1 – 152.77.159.254

152.77.160.1 – 152.77.191.254

152.77.192.1 – 152.77.223.254

 

 

 

 

Scenario 2

 

 

Number of Physical Segments:

100

 

Maximum Number of Hosts/Physical Segment:

88,000

 

Network Address:

39.0.0.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

(c) 1999 - 2001 Charles Botsford

Classroom use requires purchased license, see license agreement.

Scenario 3

 

 

Number of Physical Segments:

100

 

Maximum Number of Hosts/Physical Segment:

350

 

Network Address:

177.133.0.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

 

Scenario 4

 

 

Number of Physical Segments:

4

 

Maximum Number of Hosts/Physical Segment:

1,500,000

 

Network Address:

120.0.0.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

(c) 1999 - 2001 Charles Botsford

Classroom use requires purchased license, see license agreement.

 

Scenario 5

 

 

Number of Physical Segments:

16

 

Maximum Number of Hosts/Physical Segment:

1,500

 

Network Address:

128.199.0.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

 

 

Scenario 6

 

 

Number of Physical Segments:

250

 

Maximum Number of Hosts/Physical Segment:

100

 

Network Address:

191.254.0.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

(c) 1999 - 2001 Charles Botsford

Classroom use requires purchased license, see license agreement.

 

Scenario 7

 

 

Number of Physical Segments:

12

 

Maximum Number of Hosts/Physical Segment:

12

 

Network Address:

216.122.44.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

 

 

Scenario 8

 

 

Number of Physical Segments:

10

 

Maximum Number of Hosts/Physical Segment:

750,000

 

Network Address:

12.0.0.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

(c) 1999 - 2001 Charles Botsford

Classroom use requires purchased license, see license agreement.

 

Scenario 9

 

 

Number of Physical Segments:

50

 

Maximum Number of Hosts/Physical Segment:

600

 

Network Address:

134.119.0.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

 

 

Scenario 10

 

 

Number of Physical Segments:

3

 

Maximum Number of Hosts/Physical Segment:

25

 

Network Address:

192.177.4.0

 

 

 

 

Proposed Custom Subnet Mask:

 

 

Number of Subnets Supported:

 

 

Maximum Number of Host ID per Subnet:

 

 

Subnet IDs:

 

 

 

 

 

 

 

 

 

1st Host – Last Host on Subnet

Host ID Ranges per Subnet

 

 

 

 

 

 

 

 

 

 

(c) 1999 - 2001 Charles Botsford

Classroom use requires purchased license, see license agreement.

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