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.
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IP
Address |
Class |
Default
subnet mask |
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210.51.67.102 |
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67.23.148.0 |
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158.78.251.33 |
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145.23.117.241 |
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192.200.23.5 |
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144.225.78.1 |
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63.78.14.211 |
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192.35.128.36 |
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Determine the Custom Subnet Masks
Example Scenario
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Required # of
physical segments |
3 |
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Max # of hosts
per segment |
4000 |
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Network address |
142.25.0.0 |
|
Default subnet mask |
255.255.0.0 |
|
Proposed custom
subnet mask |
255.255.224.0 |
|
Number of subnets
supported |
6 |
|
Maximum number of
host IDs per subnet |
8190 |
Scenario One
|
Required # of
physical segments |
12 |
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Max # of hosts
per segment |
500 |
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Network address |
191.32.0.0 |
|
Default subnet
mask |
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Proposed custom
subnet mask |
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Number of subnets
supported |
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Maximum number of
host IDs per subnet |
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Scenario Two
|
Required # of
physical segments |
12 |
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Max # of hosts
per segment |
12 |
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Network address |
195.15.12.0 |
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Default subnet
mask |
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Proposed custom
subnet mask |
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Number of subnets
supported |
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Maximum number of
host IDs per subnet |
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Scenario Three
|
Required # of
physical segments |
1000 |
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Max # of hosts
per segment |
12000 |
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Network address |
12.0.0.0 |
|
Default subnet
mask |
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Proposed custom
subnet mask |
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Number of subnets
supported |
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Maximum number of
host IDs per subnet |
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Scenario Four
|
Required # of
physical segments |
28 |
|
Max # of hosts
per segment |
1500 |
|
Network address |
130.15.0.0 |
|
Default subnet
mask |
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Proposed custom
subnet mask |
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Number of subnets
supported |
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Maximum number of
host IDs per subnet |
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Scenario Five
|
Required # of
physical segments |
2 |
|
Max # of hosts
per segment |
60 |
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Network address |
199.32.18.0 |
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Default subnet
mask |
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Proposed custom
subnet mask |
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Number of subnets
supported |
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Maximum number of
host IDs per subnet |
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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
|
Required # of physical segments |
3 |
|
|
|
Max # of hosts per segment |
4000 |
|
|
|
Network address |
142.25.0.0 |
|
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|
Default subnet mask |
255.255.0.0 |
|
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Proposed custom subnet mask |
255.255.224.0 |
|
|
|
Number of subnets supported |
6 |
|
|
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Maximum number of host IDs per subnet |
8190 |
|
|
|
Subnet IDs (don’t include the invalid
subnets) |
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||
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142.25.32.0 142.25.64.0 142.25.96.0 142.25.128.0 142.25.160.0 142.25.192.0 |
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||
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Host ID Ranges Per Subnet |
Network Address |
1st Host |
Last Host on subnet |
|
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142.25.32.0 |
142.25.32.1 |
142.25.32.0 |
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142.25.64.0 |
142.25.64.1 |
142.25.95.254 |
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142.25.96.0 |
142.25.96.1 |
142.25.127.254 |
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142.25.128.0 |
142.25.128.1 |
142.25.159.254 |
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142.25.160.0 |
142.25.160.1 |
142.25.191.254 |
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142.25.192.0 |
142.25.192.1 |
142.25.223.254 |
Scenario One
|
Required # of
physical segments |
12 |
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Max # of hosts
per segment |
500 |
|
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Network address |
191.32.0.0 |
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Default subnet
mask |
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Proposed custom
subnet mask |
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Number of subnets
supported |
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Maximum number of
host IDs per subnet |
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|
Subnet IDs (don’t
include the invalid subnets) |
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Host ID Ranges
Per Subnet |
Network Address |
1st
Host |
Last Host on
subnet |
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Scenario Two
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Required # of
physical segments |
12 |
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Max # of hosts
per segment |
12 |
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Network address |
195.15.12.0 |
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Default subnet
mask |
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Proposed custom
subnet mask |
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Number of subnets
supported |
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Maximum number of
host IDs per subnet |
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Subnet IDs (don’t
include the invalid subnets) |
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Host ID Ranges
Per Subnet |
Network Address |
1st
Host |
Last Host on
subnet |
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Scenario Three
|
Required # of physical
segments |
1000 |
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Max # of hosts
per segment |
12000 |
|
Network address |
12.0.0.0 |
|
Default subnet
mask |
|
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Proposed custom
subnet mask |
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|
Number of subnets
supported |
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Maximum number of
host IDs per subnet |
|
Naw…I won’t make you
do this one. That would be evil.
Scenario Four
|
Required # of
physical segments |
6 |
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Max # of hosts
per segment |
8000 |
|
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|
Network address |
130.15.0.0 |
|
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Default subnet
mask |
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Proposed custom
subnet mask |
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|
Number of subnets
supported |
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|
Maximum number of
host IDs per subnet |
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Subnet IDs (don’t
include the invalid subnets) |
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Host ID Ranges
Per Subnet |
Network Address |
1st
Host |
Last Host on
subnet |
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Scenario Five
|
Required # of
physical segments |
2 |
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Max # of hosts
per segment |
60 |
|
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|
Network address |
199.32.18.0 |
|
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|
Default subnet
mask |
|
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Proposed custom
subnet mask |
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|
Number of subnets
supported |
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Maximum number of
host IDs per subnet |
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Subnet IDs (don’t
include the invalid subnets) |
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Host ID Ranges
Per Subnet |
Network Address |
1st
Host |
Last Host on
subnet |
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