I am working with Packet Tracer atm and have 3 subnet plans :

  • assigned(management(104users)
  • staff(43 users)
  • admin(35 users)).

I have an ip address range of: and subnet mask of I want to produce that subnet plan but with the most efficient use of the ip address range provided above.

Could anyone give me a brief idea of how to transform that range to the most efficient use of the IP addresses? I do have to implement VLAN's on each of the switches using router on stick methodology and the router interfaces will have ip's assigned from a range of – I'm a bit stuck at the moment.

The diagram looks as follows:

packet tracer

  • It's not clear what your trying to do: Are you subnetting the network, or the network? – Ron Trunk Apr 29 '16 at 13:13
  • subnetting the, sorry for my english. the range will be assigned to the router's serial interfaces – JGuerra Apr 29 '16 at 13:15
  • The first step is to figure out the smallest subnet that will hold each of your user groups. So for example, what is the smallest subnet that will hold 104 users? – Ron Trunk Apr 29 '16 at 13:24
  • 104 users refers to the management users so I would suppose 2^7=128. That will give me enough for the 104 users right? – JGuerra Apr 29 '16 at 13:30
  • these are route-able IP addresses, are you assigning them to clients? – Sum1sAdmin Apr 29 '16 at 13:31

You need, at least, 104 ips available on your subnet. What is most close to it is 128, from where you already have to remove 2 as they are going to be used for network address and broadcast address.

Having this in mind, and knowing that having a 24 bits prefix network address means having (255-2) available ips, you could only get one bit more for subnets.

The result would be:

Netmask: = /25


Hosts:      126   

 Hosts:     126

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