30 Apr how to Find network and broadcast address of an IP address?
Finding Network address and broadcast address of an IPv4 address is a challenging task if you are preparing for CCNA Global certificaton exam. It’s an important topic comes under IPv4 subnetting.
Following explanation may help you in this.
Example 1:
Class C address: 192.168.1.176/26
IP address: 192.168.1.176
Subnet mask: 255.255.255.192
Since this is a class C address, no need to focus on first 24 bits. Let’s focus on 4th octet value 176.
It is clear from the subnet mask that 2 bits from the host bits are borrowed, and used for creating subnets.
As 2 bits are borrowed, subnet block size is 64. We get 4 subnets. 0, 64, 128 and 192 with 63, 127, 191 and 255 as a respective broadcast IP address.
172 belongs to the subnet 192.168.1.128 as it is higher than 128 and lower than 191.
So the IP 192.168.1.172/26 belongs to Subnet / Network 192.168.1.128 with broadcast address 192.168.1.191.
Example 2:
Class C address: 192.168.1.176/28
IP address: 192.168.1.77
Subnet mask: 255.255.255.240
Since this is a class C address, no need to focus on first 24 bits. Let’s focus on 4th octet value 77.
It is clear from the subnet mask that 4 bits from the host bits are borrowed, and used for creating subnets.
As 4 bits are borrowed, subnet block size is 16. We get 16 subnets. 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224 and 240 with 15, 31, 47, 63, 79, 95, 111, 127, 143, 159, 175, 191, 207, 223 and 255 as a respective broadcast IP address.
77 belongs to the subnet 192.168.1.64 as it is higher than 64 and lower than 79.
So the IP 192.168.1.77/28 belongs to Subnet / Network 192.168.1.64 with broadcast address 192.168.1.79.
Example 3:
Class B address: 172.16.25.200/17
IP address: 172.16.25.200
Subnet mask: 255.255.128.0
Since this is a class B address, no need to focus on first 16 bits. Let’s focus on 3rd octet value as last bit borrowed is from this octet to create subnets.
It is clear from the subnet mask that 1 bit from the host bits is borrowed, and used for creating subnets.
As 1 bits are borrowed, subnet block size is 128. We get 2 subnets. 0.0, and 128.0 with 127.255 and 255.255 as a respective broadcast IP addresses.
25 belongs to the subnet 172.16.0.0 as it is higher than 0 and lower than 127.
So the IP 172.16.25.200/17 belongs to Subnet / Network 172.16.0.0 with broadcast address 172.16.127.255.
Now, you find out the Subnet / Network and it’s associated broadcast addresses for following IP’s.
172.16.100.145/19
172.16.80.251/21
10.10.1.79/9
10.100.231.73/12
10.78.111.200/17
10.32.48.89.23/20
10.23.90.113.174/25
10.45.29.223.24/28
If you need any help contact me on my WhatsApp: +91 9763976333. (Only messages. No video or audio calls.)
About Trainer:
Manddar Mete
Conducts Cisco Certification’s training since 2010.
Provide Networking support at professional level to various clients.
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