subnetting guru input required

[zappo0305]

We're redesign the network and debating on the subnetting topic to find out what's the best practice/design to allocate IP addresses. Obviously reserving IP address is important. Ournetworks consists of server, MPLS and VRF etc, with wireless, wired, phone, etc.

Any reply/input will make my day

Thanks to all the network legends out there.

[JohnTylerPearce]

Well, you're really going to get 100 different answers. How many servers, wireless devices, wired devices, and IP

Phones?

[Ton V Engelen]

Hi

yeah, John here is right, you bet. .

I think the best you can do is make an ip number plan.

Try to identify how many ip adressen you re going to need for each subnet:

- windows server vlan

- linux server vlan

- magamement ip's

- client subnets, maybe subnet by floor

- phones

-etc

Then, based on what you need, define a number plan. Allocate the first, lets say, 10 subnets for servers, then define the next 10 or more subnets for clients, etcetc.

Make sure there is room for some extra subnets ie, if you need 2 server subnets now, allocate 4 for future use.

It can be good practise to define the subnets in steps of 8 or 16. That way you can apply filtering easy over lets say 8 or 16 subnets. 

So, the first 8 subnets are servers, then 8 for clients etcetc.

Ofcourse, these are examples. But if you put some work in it, you get there.

Good luck.

[garapoglou]

Hi,

I would do the following:

1. Make a list of all servers you currently have. Include the number of servers you are going to add in the near future. It's an excellent opportunity to map your network if you haven't already done so. Those servers will need a VLAN of their own.

2. Make a list of all management interfaces. They will be on a VLAN of their own, different from the servers one. No other device is supposed to connect there.

3. Make a list of all clients based on the department they belong. Include future needs as well.

4. Each department will have a separate VLAN. For example, one VLAN for the Sales Department, one VLAN for the Logistics Department etc.

5. Make a list of all IP Phones including future needs too. They will work on a separate VLAN.

6. Create a VLAN for guest/collaborators and give it the proper rights.

7. Create an isolation VLAN and restrict any kind of access to the network. This will be used to connect all switchports not needed at the moment. You could shut them down, but I really like to have them up and running so I know what's going on with them.

8. Create a DMZ. It will be used by servers that access the web, such as a mail server, an antispam server etc.

9. Use dynamic IP addressing with the proper reservations for all servers and clients.

Create DHCP scopes and define IP helper addresses for all VLANs.

Always consider the future needs factor. Create subnets in such way there always are more subnets available. When hosts are not so many use the proper subnet mask to create a smaller subnet.

Best regards,

Giorgos