Subnetting a class c network 1

[Kernalx69]

Hi
I am a networkadmin on a small company wich is a member of a enterprise.
We recently bought some wireless accesspoints and now we must stop all traffic from being routed to the wan of the enterprise.

I am going to solv this with a Cisco pix 515e.

All traffic that is going from the wireless network (Vlan2) can only go to our servers and the rest of our network (Vlan1) can go anywhere.

Now the problem:
We have our own klass c network with public addresses and now i must in some way split it in three parts becasuse of the vlans and the little network between our router and the firewall.
The problem is that i don't want to split it in three equal parts because we have to many nodes in the vlan1.
And i must use public addresses in every network an we can't get more public addresses.

The most attractive distribution should be:
2 nodes in the network between the router and the firewall
180 nodes in vlan 1
60 nodes in vlan 2

I know how to subnet the network into four parts but then our networks will be to small.
If i subnet it into two parts then i have no network over for the network between the router and the firewall.


How should i do ?
Can this be done ?

 

[chieftan999]

Class C

I think is as follows:-

255.255.255.192
2 x Subnets
62 x hosts per subnet

255.255.255.224
6 x Subnets
30 x hosts per subnet

255.255.255.240
14 x Subnets
14 x hosts per subnet

255.255.255.248
30 x subnets
6 x hosts per subnet

255.255.255.252
60 x subnets
2 hosts per subnet

That about covers the Class C subnetting options using purchased addresses.

If using a private range then maybe CIDR could have helped.

Reamin positive. The affect on those around you will amaze.

 

[Kernalx69]

Thanks for your answer !

But it doesn't help me.

I know about the different subnets.

I recently read something about vlsm/cidr and i think this is the solution for me.

But you said that if i have used private range i could use CIDR.
Can't i do that if have a public range.

 

[GrnEyedLdy]

Looks like you may be in a jam here.

With a Class C address the only way to subnet it to get 180 hosts addresses on one network is by using all 8 bits in the last octect, which you obvioulsy already know. This of course does not leave you any bits to play with for the other 2 networks you need. As you stated breaking this into 4 subnetworks won't meet your company needs.

Since this won't work for you, is there any reason why your hosts can not use Internal Private IP Addresing. You could easily work this out with an Internal Class B address.

Just a thought,

Patty

 

[ChrisAC]

And i must use public addresses in every network"

Why?

Patty is spot on here.

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[Kernalx69]

Hi
Thanks for your answers !

The cause that i want public addresses is what i must because it's a directive from the Enterprise.
Don't ask me why it is this way.

I think i have found a solution now but it 'doesn't fulfil my wishes but this is the only way.

Subnet between router and firewall.
x.x.x.248/29 room for 6 nodes.

Vlan1
x.x.x.0/25 Room for 126 nodes.

Vlan2
x.x.x.128/26 Room for 62 nodes.

And 3 over smaller networks for future use.

I am not used to configure subnets like this but i have found some information on the internet and i think it would work.

What do you think ?

 

[ChrisAC]

Should be okay.

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************