Skills Exam Subnetting Practice Key
A) Given a network Address of 192.168.100.0, you need to create at least 4 usable
subnets which will support up to 30 host addresses each.
Class of Address:
Default subnet mask:
How many bits need to be left in host field:
How many bits need to be borrowed:
Custom Subnet Mask:
C
255.255.255.0
5
(25 = 32 hosts, 30 usable)
3
(23 =8 subnets, 6 usable)
255.255.255.224 (255.255.255.11100000)
List the following information for the 1st 8 subnets (including the Zero subnet)
0
1
2
3
4
5
6
7
Subnet Address
192.168.100.0
192.168.100.32
192.168.100.64
192.168.100.96
192.168.100.128
192.168.100.160
192.168.100.192
192.168.100.224
Range of Host addresses
192.168.100.1- 192.168.100.30
192.168.100.33-192.168.100.62
192.168.100.65-192.168.100.94
192.168.100.97-192.168.100.126
192.168.100.129-192.168.100.158
192.168.100.161-192.168.100.190
192.168.100.193-192.168.100.222
192.168.100.225-192.168.100.254
Broadcast Address
192.168.100.31
192.168.100.63
192.168.100.95
192.168.100.127
192.168.100.159
192.168.100.191
192.168.100.223
192.168.100.255
B) Apply the subnetting scheme to the following network diagram:
 Assign the 1st usable subnet to the WAN link between GAD and Anniston
o Assign GAD’s serial interface the 1st usable host address on this subnet
o Assign Anniston’s serial interface the 2nd usable host address on this
subnet
 Assign the 2nd usable subnet to the WAN link between GAD and Boaz
o Assign GAD’s serial interface the 1st usable host address on this subnet
o Assign Boaz’s serial interface the 2nd usable host address on this subnet
 Assign the 3rd usable subnet to Anniston’s LAN
o Assign the first usable host address on this subnet to the router’s Ethernet
interface
o Assign the management station a host address in the lower ½ of the
address range
o Assign the production station a host address in the upper ½ of the address
range
 Assign the 4th usable subnet to Boaz’s LAN
o Assign the first usable host address on this subnet to the router’s Ethernet
interface
o Assign the management station a host address in the lower ½ of the
address range
o Assign the production station a host address in the upper ½ of the address
range
GAD S 0/0
(DCE)
IP Address: 192.168.100.33
Subnet Mask: 255.255.255.224
Anniston S 0/0
(DTE)
IP Address: 192.168.100.34
Subnet Mask: 255.255.255.224
Boaz S 0/0
(DTE)
IP Address: 192.168.100.66
Subnet Mask: 255.255.255.224
Fa 0/0
IP Address: 192.168.100.97
Subnet Mask: 255.255.255.224
Management 1
IP Address: 192.168.100.100
Subnet Mask: 255.255.255.224
Default Gateway: 192.168.100.97
S 0/1
(DCE)
IP Address: 192.168.100.65
Subnet Mask: 255.255.255.224
Fa 0/0
IP Address: 192.168.100.129
Subnet Mask: 255.255.255.224
Production 1
IP Address: 192.168.100.120
Subnet Mask: 255.255.255.224
Default Gateway: 192.168.100.97
Management 2
IP Address: 192.168.100.135
Subnet Mask: 255.255.255.224
Default Gateway: 192.168.100.129
Production 2
IP Address: 192.168.100.155
Subnet Mask: 255.255.255.224
Default Gateway: 192.168.100.129