Subnetting Question

M1S0

Hi

If I require 4 networks with 500 hosts each and within those 4 networks require to split them into 12 or 14 VLANs each with a diffferent subnet each network how will it be ?

I will be very gradefull if you could explain me how you separate VLANs and assign them subnets to each please.

Thanks
M1S0

Technoracer

You would need more than just one network (172.16.2.0/23), to fit four 500 host subnets into. Using 172.16.2.0/23, 172.16.4.0/23, 172.16.6.0/23, and 172.16.8.0/23 should work.

M1S0

Ok sorry I did not change the third octet , what about the second question is it correct the subnetting
for the 172.16.2.0/23 as i did it below ?

Technoracer

Technoracer wrote: »

You would need more than just one network (172.16.2.0/23), to fit four 500 host subnets into. Using 172.16.2.0/23, 172.16.4.0/23, 172.16.6.0/23, and 172.16.8.0/23 should work.

The subnet number is the number before your first host number, so you cona't make it an x.x.x.0 every time. For example, if your fist host is 172.16.2.129, then your network/subnet is 172.16.2.128, not 172.16.2.0.

Gngogh

M1S0 wrote: »

Hi

If I require 4 networks with 500 hosts each the subnets would be:

172.16.2.0/23
172.16.2.0/23
172.16.2.0/23
172.16.2.0/23

and within those 4 networks require to split them into 12 or 14 VLANs each with a diffferent subnet each network will it be like that:

VLANS Hosts Network
1 90 172.16.2.1 - 172.16.2.127 172.16.2.0 / 25 255.255.255.128
2 20 172.16.2.129 - 172.16.2.159 172.16.2.0 / 27 255.255.255.224
3 20 172.16.2.161 - 172.16.2.191 172.16.2.0 / 27 255.255.255.224
4 16 172.16.2.193 - 172.16.2.123 172.16.2.0 / 27 255.255.255.224
5 14 172.16.2.193 - 172.16.2.223 172.16.2.0 / 27 255.255.255.224
6 12 172.16.2.225 - 172.16.2.255 172.16.2.0 / 27 255.255.255.224
7 12 172.16.3.1 - 172.16.3.31 172.16.3.0 / 27 255.255.255.224
8 12 172.16.3.33 - 172.16.3.63 172.16.3.0 / 27 255.255.255.224
9 12 172.16.3.65 - 172.16.3.85 172.16.3.0 / 27 255.255.255.224
10 2 172.16.3.87 - 172.16.3.91 172.16.3.0 / 30 255.255.255.252
11 2 172.16.3.93 - 172.16.3.97 172.16.3.0 / 30 255.255.255.252
12 2 172.16.3.99 - 172.16.3.103 172.16.3.0 / 30 255.255.255.252
13 1 172.16.3.105 - 172.16.3.107 172.16.3.0 / 31 255.255.255.252
14 1 172.16.3.109 - 172.16.3.111 172.16.3.0 / 31 255.255.255.252

I will be very gradefull if you could explain me how you separate VLANs and assign them subnets to each please.

Thanks
M1S0

Hi,

Part 1.

172.16.2.0/23 = 172.16.2.0 - 172.16.3.255 subnetmask 255.255.254.0 ( 510 host )

Part 2.

172.16.2.0/25 = 172.16.2.0 - 172.16.2.127 subnetmask 255.255.255.128 ( 126 host )
172.16.2.128/26 = 172.16.2.128 - 172.16.2.191 subnetmask 255.255.255.192 ( 62 host )
172.16.2.192/27 = 172.16.2.192 - 172.16.2.223 subnetmask 255.255.255.224 ( 30 host )
172.16.2.224/27 = 172.16.2.224 - 172.16.2.255 subnetmask 255.255.255.224 ( 30 host )

172.16.3.0/27 = 172.16.3.0 - 172.16.3.31 subnetmask 255.255.255.224 ( 30 host )
172.16.3.32/27 = 172.16.3.32 - 172.16.3.63 subnetmask 255.255.255.224
172.16.3.64/26 = 172.16.3.64 - 172.16.3.127 subnetmask 255.255.255.192 (62 host )
172.16.3.128/28 = 172.16.3.128 - 172.16.3.143 subnetmask 255.255.255.240 (14 host )
172.16.3.144/28 = 172.16.3.144 - 172.16.3.159 subnetmask 255.255.255.240
172.16.3.160/27 = 172.16.3.160 - 172.16.3.191 subnetmask 255.255.255.224 (30 host )
172.16.3.192/27 = 172.16.3.192 - 172.16.3.223 subnetmask 255.255.255.224
172.16.3.224/29 = 172.16.3.224 - 172.16.3.231 subnetmask 255.255.255.248 ( 6 host )
172.16.3.232/29 = 172.16.3.232 - 172.16.3.239 subnetmask 255.255.255.248
172.16.3.240/30 = 172.16.3.240 - 172.16.3.243 subnetmask 255.255.255.252 ( 2 host )
172.16.3.244/30 = 172.16.3.244 - 172.16.3.247 subnetmask 255.255.255.252
172.16.3.248/30 = 172.16.3.248 - 172.16.3.251 subnetmask 255.255.255.252
172.16.3.252/30 = 172.16.3.252 - 172.16.3.255 subnetmask 255.255.255.252

vlan 13 and 14 have the wrong subnetmask it should be 255.255.255.254 and they can only accommodate 1 host

vlan 4 and 5 are the same.. with a error on vlan 4.

the starting addresses are wrong on all of them.

M1S0

Hi Gngogh

Thanks a lot for your help now it make sense I released my mistake.

Gngogh

M1S0 wrote: »

Hi Gngogh

Thanks a lot for your help now it make sense I released my mistake.

Can I ask you something about packet tracer by cisco as well please.

If I have servers do I use one vlan for all of them or i assign to each server a VLAN.

Thanks
M1S0

I m not an expert, but i would put all the servers in the same vlan.
if you are using a dhcp server to assign all the ip addresses to the different networks, you will need a router to forward request to the dhcp server ( you might be able as well to do this with layer 3 switch ). if you dont know how to setup intervlan routing, then you should put a dhcp server for each vlan.

Gngogh

send me your packet tracer file or post a print screen..

Gngogh

is that a school project????

Gngogh

all you have is to subnet 172.16.2.0/24 according to your excel file...

Gngogh

M1S0 wrote: »

hi sorry I tried to email you not sure if you got , i did the excel file but I want to use the /23 to have more ip addresses in case the organisation wants to expand , is that wrong ?

no its not wrong, its correct... i have subneted according to your excel file and in reality you need /23.. it is impossible to have all those subnet in a /24, because you cannot forget about the switches, they also need a ip address for management.

M1S0

thank you very much Gngogh

if i want to add wireless network as well what will it be the situation then?

Gngogh

to add a wireless network, the wireless router will have a ip address from the network 172.16.2.0/23 and the wireless clients will have 192.168.10/24 or any other private ip address that you can configure on the wireless router.