The charge for PUBLIC IPs out in the real-world is supposed to cover administration costs. LEAs are probably (no guarantee) doing exactly the same thing when "selling" private IPs. There is work involved in handing out addresses, sorting out routing etc... and if that is sub-contracted to commercial orgs, that'll be who you're ultimately paying. It's a trade off between that cost and the cost (+ other potential benefits) of how much time it will take to throw in your own NAT box and configure everything you need to run across it properly. I suspect difficulties with the latter is one reason why county/LEA might hate schools with NAT boxes.
We are in South Africa, we don't have LEAs (to be honest, I don't even know what that is or what it stands for) and so we don't have to pay for IP Leases
What I meant was
I can setup one scope, say, 192.168.0.x for Servers
192.168.1.x for WiFi Routers
192.168.2.x for Printers
192.168.3.x for PCs
So theoretically, i would only set 192.168.3.x to actual have addresses available for leaseing, all the others would have to be set manually and have static IPs.
but what if I wanted to introduce 192.168.4.x for laptops
Is there anyway I can setup something somewhere or somehow so laptops are assigned from 192.168.4.x and PCs from 192.168.3x
Thinking about it, I would say no, there is no way of doing without manually setting each IP (static IPs).
Or you would setup a revision for them.
Yes. In DHCP you make a new record manually, and you put a mac address of the device and then assign an IP address. You set the device to pickup a DHCP IP address and every time it asks for an IP from the server it will get the one you assigned.
Nick_Parker (1st March 2008)
LEA = Local Education AuthorityWe are in South Africa, we don't have LEAs (to be honest, I don't even know what that is or what it stands for)
RBC = Regional Broadband Consortium
Don't know/think it's universal in the UK, but in this context one of the above is running what is typically a big private intranet and school networks are connected to that. There will likely be serious firewalls between the intranet and Internet, central web caches, DNS, time services etc. Because managing that intranet takes effort a school may well have to pay for getting new blocks of IP addresses, which is just the same getting IP addresses when you have a public connection from an ISP (in either case that cost may be hidden in some annual charge rather than explicit). LEAs tend to be a school tech's psychological "out-group", the common enemy they can get together and whine about. Sometime's that is justified, sometimes it's just whining. You often see the same effect further down the food-chain i.e. teachers/staff vs. school techs.
Anyway... I think having ranges for statically configured devices is sensible (printers, servers, WAPs, switches etc.) but I wouldn't bother trying to distinguish between laptops and PCs via their IP address - you can do that with their computer name/DNS e.g. LAPTOP-27, SCIENCE-03, OFFICE-01.
If you must have different IP addresses for Laptops then I'd be thinking about putting the wireless infrastructure on a separate (routed) subnet.
The problem is, the DHCP server has to distinguish between a printer, a desktop, a laptop etc... How can it know other than via a manual list of MAC address reservations (or, if you wish to not use static IP's, via an IAS server, managed switches and MAC address authentication)?
Somehow, the server would have to be told what devices get what. The small scale way of doing this is to create reservations. The large scale way is as I stated above. I have an IAS server which looks at a list of allowed devices when a computer connects to the network. It then assigns it to the relevant VLAN and from that the DHCP server knows which DHCP scope to serve an address from.
However, I don't pay attention really to the IP addresses for identifying machines, as computer names are much more useful. I implemented the above to provide some form of authentication and to segment the network.
FN-GM (1st March 2008)
If i was you i would have 3 ranges.
1 Range for Static IPs (Such as servers etc)
2 Ranges for DHCP Clients
I configure printers, WAPs, switches etc. with static IPs and keep a record of them by manually creating DNS entries in zones created for such devices. Alternatively just give them DHCP reservations.The DHCP server has to distinguish between a printer, a desktop, a laptop etc... How can it know other than via a manual list of MAC address reservations
PS: Given a choice of private IP address space I'd use something from 10/8. You can get (and I've seen some annoying) conflicts with factory-default addresses in 192.168/16.
Thanks for all your suggestions guys!
What I'm going to try do is create a scope with the following addresses: 192.168.0.1 - 192.168.3.254
Subnet Mask of 255.255.252.0
I'm going to use 192.168.0.x for Servers, WAP, Printers (via reservations)
and use 192.168.2.x and 192.168.3.x for PCs/Laptops
I.e. make the actual distributable pool from 192.168.2.1 -> 192.168.3.254
what do you think?
Last edited by Nick_Parker; 1st March 2008 at 10:48 PM. Reason: mistake in IP address
why not use 192.168.1.x for servers? if you use 192.168.0.x for reservations i think you will need to include that in the scope but set it as an excluded range.
As Above, set the scope as 192.168.1.1 - 192.168.3.254, with a subnet of 22.214.171.124.
By creating the DHCP distributable pool from 192.168.2.1 - 192.168.3.254, this leaves the 192.168.1.x range free. This is where you should allocate servers, printers, wireless access points static IPs. No reservations are needed as they'd be outside the DHCP distributable pool.
Generally speaking, I'd set servers in the 192.168.1.5x range, printers in the 192.168.1.6x range and access points in the 192.168.1.7x and so on.
Hope this helps!
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