Subnetting IPV4 Address using VLSM

VLSM is a technique used in IPV4 subnetting to create networks domains while ensuring devices are allocated IP addresses with little broadcast domains.

VLSM makes it possible to allocate the required number of IP addresses.

To determine the number of IP addresses or host we use binary values.

Steps for subnetting

1. To determine the number of hosts required in the LAN.

125+59+12+2+2+2+25 = 227 hosts IP addresses

2.?Identify the class of IP address required.

The given IP address is 172.16.1.0/24

The number of IP addresses is 2^8 -2 = 254 IP addresses which fulfils our requirement of address space.

To get the number of host IP addresses for 125 hosts we refer binary values that is 128 – 2 = 126 hosts

Similarly for 59 hosts, we have 64-2 = 62 hosts

For Management (12 hosts), we have 16 – 2 = 14 hosts

For DMZ network (25 hosts), we have 32 – 2 = 30 hosts.

For WAN links each we have:

4 – 2 = hosts

4 – 2 = hosts

4 – 2 = 2 hosts

3.????? Determine the subnet starting with highest number of hosts

172.16.1.0/25 (128 -2 hosts) 11111111.11111111.11111111.10000000/25

This means the networks will go up by 128

172.16.1.128/26 (64 -2 hosts) 11111111.11111111.11111111.11000000/26 Borrow 1 host bit

172.16.1.192/27 (32 -2 hosts) 11111111.11111111.11111111.11100000/27. This means the network will go up by 64

172.16.1.224/28 (16 -2 hosts) 11111111.11111111.11111111.11111000/28. This means that the network will go up by 32

The remaining networks go up by 4 because of the number of host bits

172.16.1.240/30 (4 -2 hosts) 11111111.11111111.11111111.11111100/30

172.16.1.244/30 (4 -2 hosts) 11111111.11111111.11111111.11111100/30

172.16.1.248/30 (4 -2 hosts) 11111111.11111111.11111111.11111100/30

?For more information on subnetting using VLSM use this link: https://study-ccna.com/variable-length-subnet-mask-vlsm/

While this technique can be cumbersome and time-consuming you can prefer having a DCHPV4 or DHCPV6 server for automatic assignment of IP address within your network.