setup different network IP address

Dear experts,

I wish to obtain some information about network setup when there are different IP ranges.

What is proper way to setup IP ranges 192.168.1.x, 192.168.2.x, 192.168.3.x, all the way up to 192.168.10.x

1. do I need or is it better to separate switches for each of the IP range?
2. do I configure the IP range in firewall/router or in switches?
3. If I specify each port on my firewall for each of the IP range and connect all ports to the back of a 48 port switch what will happen?
    - will the network devices obtain the IP from any of those ranges as in 192.168.1.x to 192.168.10.x?
    - does the assigning of the IP depends on the DNS server? (if the DNS server is on 192.168.1.x then all network devices will be assigned to 192.168.1.x)
4. any additional references for network information will be great. Thanks
Kinderly WadeprogrammerAsked:
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Fred MarshallPrincipalCommented:
1. Don't need separate switches or copper wires.  Common practice is separate both.  VLANs are a way to do with the same switch / different ports and therefore different copper wires.
2. Level 2 switches don't care about IP addresses (except to be configured or managed themselves and, at that, need not be on any used LAN subnet.  It's just more convenient for you is all).  Level 3 switches are more like routers.....
3. I believe you mean "If I specify each port on my firewall for each of the IP subnets" as a VLAN and connect each port to a separate 48-port switch" what will happen:
   - then you will have a switch for each VLAN/subnet.
  .. - will the network devices obtain the IP from any of those ranges as in 192.168.1.x to 192.168.10.x?
        Not this way.  Each subnet will be separate.
  .. - - does the assigning of the IP depends on the DNS server? (if the DNS server is on 192.168.1.x then all network devices will be assigned to 192.168.1.x)
        No.  The DNS server address has little to do with all this - except if it's the same for all subnets then there's some routing to be done.  Consider the DHCP server role which should provide a DNS address.  

Maybe you meant what if all the VLANs from the firewall are plugged into the same 48-port switch?  Then it depends on what kind of switch it is.  
- If it's a dumb "smart" switch with no VLANs, etc, then all the subnets will be available on that switch on all the ports.  Maybe that rather defeats the purpose of the VLANs in the first place and maybe not .. depends on what you want to do.  But it would be unusual.
- If it's a managed switch with VLAN capability then presumably some number of ports would be assigned to each VLAN / subnet corresponding to the firewall setup / ports.

The gateway will be on the local LAN/subnet.  That's a requirement.
The DNS server address can be anywhere that's reachable.  So, it can be an internet address but perhaps NOT a local LAN/subnet address that's on a different subnet than the client machine - without routing for that purpose.

Beyond this, a lot depends on the capabilities of your equipment.
You seem to be asking "What if I connect a bunch of different LAN gateways to the same switch in common (without VLANs)?"  This implies a bunch of different DHCP servers.  
I think a fair answer is:  "I wouldn't suggest it because it's so uncommon that you won't get good advice.  And, one can't say completely without the individual equipments and settings and connections.  Nobody really can answer this question very well at all."

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Bryant SchaperCommented:
I would like a bit more info as well.

What is the goal to separate the networks, and how many devices are we talking about.

But based on the initial questions, and I will just assume we are working with Cisco switches although most HP, Juniper or Cisco switches will have the feaures.

 1.  No need to separate the physical hardware, you will be using VLANS to set this up with access ports and trunk ports.

 2.  This depends on the firewall, but the router the router will need a sub interface on each network so they can communicate.  Your firewall may need this as well depending on how you connect your network and use nat
 3. Do you mean switch, then yes you specify their vlan
     - You endpoint can get IP addresses for each VLAN, in cisco this is an IP helper address and sites and services in AD along with the setup in DHCP will allow the DHCP server to issue IP addresses for each subnet.  Basically the router will forward the DHCP packet to the server with the source interface address so DHCP knows to respond with an IP from that subnet.
     - No, DHCP and AD.  DNS can be supplied to an endpoint via DHCP.
4. Big topic, try googling VLAN setup and DHCP multiple subnets for more info.
David SpigelmanPresident / CEOCommented:
Really, it all depends on the mask, and what you're actually trying to accomplish. So can you explain why you want to have the separate network ranges? Do you want them to be able to communicate with each other? (e.g. Do you want to be able to reach Do you need to keep some of those devices from communicating with others?

What are you trying to accomplish?
Kinderly WadeprogrammerAuthor Commented:
Hi Doughboy,

Yes I may want them to communicate with one another. For example, I am setting up the subnet range of 192.168.1.x for all company workstations, file servers, sql servers, DSN/AD, etc....., subnet range of 192.168.7.x for my IP cameras, subnet range of 192.168.5.x for my IP phones. I have a PC installed with IP Camera softwares and I wish to retrieve those backup data from time to time from subnet 192.168.1.x.

Do you have any suggestions? Thanks
Fred MarshallPrincipalCommented:
The most fundamental way to do that is to route packets between the subnets.
The simplest form or "classical approach" would be:

Subnet A <>  router <> Subnet B

An inter-subnet router would be set up to work in "router" mode / no NAT.
One port (lets use a LAN port on a typical router) would have IP address on Subnet A.
Another port (lets use the WAN port on a typical router) would have IP address on Subnet B.
Then, the gateway router on each subnet would direct packets to its respective inter-subnet router's IP address.

Then, if there are other subnets, they might be added in some fashion:

Here's one way to do that.  It's not elegant but it works.  It introduces an "Interim Subnet" which is not any subnet in use otherwise.

Subnet A <> inter-subnet Router A LAN port <>  inter-subnet Router A WAN port <> Interim Subnet e.g.
Then, connect all of the inter-subnet router WAN ports to a single switch.

The inter-subnet routers would have:

etc. where I have selected the Interim Subnet addresses to match their respective network subnets
1:1, 5:5, 7:7

Then, in each inter-subnet router you would have routes with this example for the router at to to

This approach can be handy if you're using something like MPLS where the "cloud" acts like a switch (in which case you don't need another switch).

Either way once these ideas are clear then you might be able to use your actual equipment to implement the connectivity using VLANs, etc.  But then it gets more specific.
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