Last Usable = 10.118.31.254 (10.118.31.255 Is the Broadcast)

1. Enter the last usable host on the network of which the host 10.118.26.169/19 is a part.

Bits / Block Size / Exponents / Decimal Mask Value / Short Hand / Mask
0 / 1 / 255 / /32 / 255.255.255.255
1 / 2 / 254 / /31 / 255.255.255.254
2 / 4 / 252 / /30 / 255.255.255.252
3 / 8 / 248 / /29 / 255.255.255.248
4 / 16 / 240 / /28 / 255.255.255.240
5 / 32 / 224 / /27 / 255.255.255.224
6 / 64 / 192 / /26 / 255.255.255.192
7 / 128 / 128 / /25 / 255.255.255.128
8 / 256 / /24 / 255.255.255.0
9 / 512 / /23 / 255.255.254.0
10 / 1024 / /22 / 255.255.252.0
11 / 2048 / /21 / 255.255.248.0
12 / 4096 / /20 / 255.255.240.0
13 / 8192 / /19 / 255.255.224.0
14 / 16384 / /18 / 255.255.192.0
15 / 32768 / /17 / 255.255.128.0

Range = 10.118.0.0-10.118.31.255

Last usable = 10.118.31.254 (10.118.31.255 is the broadcast)

2. What is the shorthand corresponding to a subnet mask of 255.252.0.0?

255.252.0.0 = 14 bits for network, so the shorthand is /14

3. Enter the usable host range for the network of which the IP address 192.168.173.236 255.255.255.248 is a part.

The increment is 8, with 6 usable addresses per subnet

Range = 192.168.173.232 – 192.168.173.239

First usable 192.168.173.233

4. Enter the usable host range for the network of which the IP address 172.16.49.40 255.255.255.192 is a part.

Increment is 64 with 62 usable hosts per subnet

Range = 172.16.49.0-172.16.49.63

First host = 172.16.49.1

5. Enter the maximum number of valid subnets and usable hosts per subnet that you can get from the network
172.21.0.0 255.255.240.0.

255.255.240.0 = 20 network bits. Each subnet will have 4094 usable hosts and with the class B address, there are 4 bits remaining on the network side, so we have 16 subnets.

6. Enter the broadcast address for the network 172.26.121.0/25.

Network range 172.26.121.0-172.26.121.127

Broadcast is all ones in the host side, the last address 172.26.121.127

7. Enter the first usable host address on the network 10.207.14.236 255.255.255.252.

Network increment will be 4, so the network range is 10.207.14.236-10.207.14.239

First usable is 10.207.14.237

8. Enter the network address of the subnet to which the host 172.22.147.239/18 belongs.

18 bits on the network side, so the network range is 172.22.128.0-172.22.191.255

The network address is the unusable first address of 172.22.128.0

9. Enter the first usable host on the network 172.21.0.0 255.255.128.0.

Bits / Block Size / Exponents / Decimal Mask Value / Short Hand / Mask
0 / 1 / 255 / /32 / 255.255.255.255
1 / 2 / 254 / /31 / 255.255.255.254
2 / 4 / 252 / /30 / 255.255.255.252
3 / 8 / 248 / /29 / 255.255.255.248
4 / 16 / 240 / /28 / 255.255.255.240
5 / 32 / 224 / /27 / 255.255.255.224
6 / 64 / 192 / /26 / 255.255.255.192
7 / 128 / 128 / /25 / 255.255.255.128
8 / 256 / /24 / 255.255.255.0
9 / 512 / /23 / 255.255.254.0
10 / 1024 / /22 / 255.255.252.0
11 / 2048 / /21 / 255.255.248.0
12 / 4096 / /20 / 255.255.240.0
13 / 8192 / /19 / 255.255.224.0
14 / 16384 / /18 / 255.255.192.0
15 / 32768 / /17 / 255.255.128.0

17 network bits, the network range is 172.21.0.0-172.21.127.255

First usable is 172.21.0.1

10. What subnet mask would you use for the 172.19.0.0 network, such that you can get 1210 subnets and 30 hosts per subnet?

Bits / Block Size / Exponents / Decimal Mask Value / Short Hand / Mask
0 / 1 / 255 / /32 / 255.255.255.255
1 / 2 / 254 / /31 / 255.255.255.254
2 / 4 / 252 / /30 / 255.255.255.252
3 / 8 / 248 / /29 / 255.255.255.248
4 / 16 / 240 / /28 / 255.255.255.240
5 / 32 / 224 / /27 / 255.255.255.224
6 / 64 / 192 / /26 / 255.255.255.192
7 / 128 / 128 / /25 / 255.255.255.128
8 / 256 / /24 / 255.255.255.0
9 / 512 / /23 / 255.255.254.0
10 / 1024 / /22 / 255.255.252.0
11 / 2048 / /21 / 255.255.248.0
12 / 4096 / /20 / 255.255.240.0
13 / 8192 / /19 / 255.255.224.0
14 / 16384 / /18 / 255.255.192.0
15 / 32768 / /17 / 255.255.128.0

30 hosts per subnet would be 5 bits in the host side, leaving 11 bits on the network side plus the remaining 16 bits (from class B address), Subnet mask will be 27 bits or 255.255.255.224