Broadcast Address

Broadcast Address

To find the broadcast address of an interface of a router, type the command show interfaces. The command show interfaces will provide the IP address and mask for each interface. You can then calculate the broadcast address from those IP address and mask.
RIPv1’s update packet destination address is the broadcast address 255.255.255.255.
RIPv2 – 224.0.0.9
OSPF – 224.0.0.5
EIGRP - 224.0.0.10
224.0.0.6 is used when sending LSAs to the DR/BDR.

Example 1:
What is the broadcast address of the network 172.16.100.0 255.255.255.128?
Example 2:
What is the broadcast address of the network 172.16.144.0 255.255.248.0?
Example 3:
What is the broadcast address of the network 172.17.17.0/24?
Example 4:
What is the broadcast address of the network 172.17.53.112 255.255.255.240?
Example 5:
What is the broadcast address of the network 172.21.192.0 255.255.248.0?
Example 6:
What is the broadcast address of the network 172.23.0.0 255.255.254.0?
Example 7:
What is the broadcast address of the network 172.23.6.224/27?
Example 8:
What is the broadcast address of the network 172.23.171.224/27?
Example 9:
What is the broadcast address of the network 172.23.200.48 255.255.255.240?
Example 10:
What is the broadcast address of the network 192.168.88.80/29?
Example 11:
What is the broadcast address of the address 192.168.192.10/29?
Example 12:
What is the broadcast address of the network 192.168.182.0/26?
Example 13:
What is the broadcast address of the network 192.168.202.112 255.255.255.248?
Example 14:
What is the broadcast address of the network 192.168.203.240 255.255.255.240?
Example 15:
What is the broadcast address of the network 192.168.206.184/29?

Class B

Example 1:

What is the broadcast address of the network 172.16.100.0 255.255.255.128?

Solution:

Class B addresses use a default mask  of 255.255.0.0.
  Given subnet mask  = 255.255.255.128(/25)
  Block size = 256-128 = 128, means  we have a block
  size of 128 in the forth octet.
  0 is divisible by 128.
  That is 172.16.100.0/25 is a  network address.
  Next subnet address = 172.16.100.128/25
  Broadcast address is 172.16.100.127/25 of 172.16.100.0/25 network.
 The broadcast  address is: 172.16.100.127
    

Example 2:

What is the broadcast address of the network 172.16.144.0 255.255.248.0?

Solution:

Class B addresses  use a default mask of 255.255.0.0.
  Given subnet mask  = 255.255.248.0(/21) 
  Block size  = 256-248 = 8, means we have a block 
  size of 8 in the third  octet. 
  144 is divisible by 8.
  That is 172.16.144.0/21 is a network  address.
  Next subnet address = 172.16.152.0/21.
  Broadcast address is 172.16.151.255/21  of 172.16.144.0/21 
  network.
  The broadcast  address is: 172.16.151.255.
    

Example 3:

What is the broadcast address of the network 172.17.17.0/24?

Solution:

  Class B addresses  use a default mask of 255.255.0.0.
  Given subnet mask  = 255.255.255.0(/24)
  Block size = 256-255 = 1,  means we have a block
  size of 1 in the third octet.
  17 is divisible by 1.
  That is 172.17.17.0/24 is a  network address.
  Next subnet address = 172.17.18.0/24.
  Broadcast address is 172.17.17.255/24 of 172.17.17.0/24
  network.
  The broadcast  address is: 172. 17. 17. 255
    

Example 4:

What is the broadcast address of the network 172.17.53.112 255.255.255.240?

Solution:

  Class B addresses  use a default mask of 255.255.0.0.
  Given subnet mask  = 255.255.255.240(/28)
  Block size  = 256-240 = 16, means we have a block
  size of 16 in the  forth octet.
  112 is divisible by 16.
  That is 172.17.53.112/28 is a  network address.
  Next subnet address = 172.17.53.128/28
  Broadcast address is 172.17.53.127/28 of 172.17.53.112/28
  network.
  The broadcast  address is: 172.17.53.127
    

Example 5:

What is the broadcast address of the network 172.21.192.0 255.255.248.0?

Solution:

  Class B addresses  use a default mask of 255.255.0.0.
  Given subnet mask  = 255.255.248.0(/21)
  Block size = 256-248 = 8,  means we have a block
  size of 8 in the third octet.
  192 is divisible by 8.
  That is 172.21.192.0/21 is a  network address.
  Next subnet address = 172.21.200.0 /21.
  Broadcast address is 172.21.199.255/21 of 172.16.144.0/21
  network.
  The broadcast  address is: 172.  21. 199. 255
    

Example 6:

What is the broadcast address of the network 172.23.0.0 255.255.254.0?

Solution:

  Class B addresses  use a default mask of 255.255.0.0.
  Given subnet mask  = 255.255.254.0(/23)
  Block size = 256-254 = 2,  means we have a block
  size of 2 in the third octet.
  0 is divisible by 2.
  That is 172.23.0.0/23 is a  network address.
  Next subnet address = 172.23.2.0/23
  Broadcast address is 172.23.1.255/23 of 172.23.0.0/23 network.
  The broadcast  address is: 172. 23. 1. 255
    

Example 7:

What is the broadcast address of the network 172.23.6.224/27?

Solution:

  Class B addresses  use a default mask of 255.255.0.0.
  Given subnet mask  = 255.255.255.224(/27)
  Block size  = 256-224 = 32, means we have a block
  size of 32 in the  forth octet.
  224 is divisible by 32.
  That is 172.23.6.224/27 is a  network address.
  Next subnet address = 172.23.6.256/27
  Broadcast address is 172.23.6.255/27 of 172.23.6.224/27
  network.
  The broadcast  address is: 172.23.6.255
    

Example 8:

What is the broadcast address of the network 172.23.171.224/27?

Solution:

  Class B addresses  use a default mask of 255.255.0.0.
  Given subnet mask  = 255.255.255.224(/27)
  Block size = 256-224 = 32,  means we have a block
  size of 32 in the forth octet.
  224 is divisible by 32.
  That is 172.23.171.224/27 is a  network address.
  Next subnet address = 172.23.171.256/27
  Broadcast address is 172.23.171.255/27 of 172.23.171.224/27
  network.
  The broadcast  address is: 172.23.171.255
    

Example 9:

What is the broadcast address of the network 172.23.200.48 255.255.255.240?

Solution:

  Class  B addresses use a default mask of 255.255.0.0.
  Given  subnet mask = 255.255.255.240(/28)
  Block size = 256-240 = 16,  means we have a block
  size of 16 in the forth octet.
  48 is  divisible by 16.
  That is 172.23.200.48/28 is a  network address.
  Next subnet address = 172.23.200.64/28.
  Broadcast address is 172.23.200.63/28 of 172.23.200.48/28
  network.
  The broadcast  address is: 172.  23. 200. 63
    

Class C

Example 10:

What is the broadcast address of the network 192.168.88.80/29?

Solution:

  Class  C addresses use a default mask of 255.255.255.0.
  Given  subnet mask = 255.255.255.248(/29) 
  Block size = 256-248 = 8,  means we have a block 
  size of 8 in the forth octet. 
  80 is  divisible by 8.
  That is 192.168.88.80/29 is a  network address.
  Next subnet  address = 192.168.88.88/29.
  Broadcast  address is 192.168.88.87/29 of 192.168.88.80/29 
  network.
  The  broadcast address is: 192.  168. 88. 87
    

Example 11:

What is the broadcast address of the address 192.168.192.10/29?

Solution:

  Class  C addresses use a default mask of 255.255.255.0.
  Given  subnet mask = 255.255.255.248(/29) ( forth octet)
  Block size = 256-248 = 8,  means we have a block
  size of 8 in the forth octet.
  That is 192.168.192.8/29  is a network address.
  Next subnet  address = 192.168.192.16/29
  Broadcast  address is 192.168.192.15/29 of 192.168.192.8/29
  network.
  The  broadcast address is: 192.  168. 192. 15
    

Example 12:

What is the broadcast address of the network 192.168.182.0/26?

Solution:

  Class  C addresses use a default mask of 255.255.255.0.
  Given  subnet mask = 255.255.255.192(/26)
  Block size = 256-192 = 64,  means we have a block
  size of 64 in the forth octet.
  0 is  divisible by 64.
  That is 192.168.182.0/26 is a  network address.
  Next subnet  address = 192.168.182.64/26.
  Broadcast  address is 192.168.182.63/26  of
  192.168.182.0/26 network.
  The  broadcast address is: 192.  168. 182. 63
    

Example 13:

What is the broadcast address of the network 192.168.202.112 255.255.255.248?

Solution:

  Class C addresses  use a default mask of 255.255.255.0.
  Given  subnet mask = 255.255.255.248(/29)
  Block size = 256-248 = 8,  means we have a block size of 8
  in the forth octet.
  112 is  divisible by 8.
  That is  192.168.202.112/29 is a network address.
  Next subnet  address = 192.168.202.120/29.
  Broadcast  address is 192.168.202.119/29 of 192.168.202.112/29
  network.
  The  broadcast address is: 192. 168. 202. 119
    

Example 14:

What is the broadcast address of the network 192.168.203.240 255.255.255.240?

Solution:

  Class  C addresses use a default mask of 255.255.255.0.
  Given  subnet mask = 255.255.255.240(/28)
  Block size = 256-240 = 16,  means we have a block size of 16
  in the forth octet.
  240 is  divisible by 16.
  That is 192.168.203.240/28 is a  network address.
  Next subnet  address = 192.168.203.256/28
  Broadcast  address is 192.168.203.255/28 of 192.168.203.240/28
  network.
  The  broadcast address is: 192. 168. 203. 255
    

Example 15:

What is the broadcast address of the network 192.168.206.184/29?

Solution:

  Class  C addresses use a default mask of 255.255.255.0.
  Given  subnet mask = 255.255.255.248(/29)
  Block size = 256-248 = 8,  means we have a block size of 8
  in the forth octet.
  184 is  divisible by 8.
  That is 192.168.206.184/29 is a  network address.
  Next subnet  address = 192.168.206.192/29
  Broadcast  address is 192.168.206.191/29  of 192.168.206.184/29
  network.
  The  broadcast address is: 192. 168. 206. 191
    

Excercise

Question 1:

What is the broadcast address of the subnet address 192.168.99.20 255.255.255.252?

Answer:

192. 168. 99. 23

Question 2:

What is the broadcast address of the network 172.24.27.48/28?

Answer:

172. 24. 27. 63

Question 3:

What is the broadcast address of the network 172.25.100.0 255.255.255.0?

Answer:

172. 25. 100. 255

Question 4:

What is the broadcast address of the network 172.27.116.0 255.255.254.0?

Answer:

172. 27. 117. 255

Question 5:

What is the broadcast address of the network 172.27.244.0/23?

Answer:

172. 27. 245. 255

Question 6:

What is the broadcast address of the network 172.30.232.0 255.255.252.0?

Answer:

172. 30. 235. 255

Question 7:

What is the broadcast address of the network 172.31.54.192/27?

Answer:

172. 31. 54. 223

Question 8:

What is the broadcast address of the network 192.168.213.224 255.255.255.224?

Answer:

192. 168. 213. 255

Question 9:

What is the broadcast address of the network 192.168.248.128/26?

Answer:

192. 168. 248. 191