Running out of (private) addresses on College LAN
We have come up against a problem, which I am sure must be fairly common, but I have been unable to find any good documentation/guides on options, and on how best to deal with it.
Basically, when the network at the main College site was first setup it was done using an class C IP address range (funnily enough it's not a private range, but a public one we which we no longer own and may be used elsewhere on the Internet, but that's another matter). This limits us to 254 hosts on the network.
Anyway, with steady expansion over the years, we now find that we are running out of IP adresses (the DHCP server was regularily running out) causing serious problems with laptops/PCs not working on the network. For the moment I have addressed this by setting the lease period to 30 minutes, and we have an autoshutdown system (primarily used to save power) to to turn PCs after 35 mins of idletime (on the logon screen).
But it's not going to keep things going for much longer, as there is need for further expansion (e.g. PCs and Wifi access points). We cannot deploy additonal access points, even though we have them, because it will tip the no. of IP addresses over the limit too often. So as you can see we are up against a problem. I have considered:
- Changing to IP range to private/16 (e.g. 172.16.0.0) thus giving us around 65,000 IP addresses (I think). But this sounds like a big job, we'd need to change the IP addresses on all static devices, servers.
- Setting up routing to split the network into two; but what is the best way/device to do this? We have a Netgear WiFi Controller which manages our WAPs. I wondered if we could use this to hand out a different range IP addresses to all WiFi devices. But having looked that the config/docs, I don't understand how to do it; not being very familar with VLANs. Netgear ProSafe support don't sound too sure either; one said we would definately need to plug the Netgear Controller into a physical router device.
- We do have several routers already (to route traffic to the 3 other College sites), would it be feasible to use one of these? I'm not sure but with them being very old, their Ethernet ports may only work at 10Mbit (10BaseTX) so it may cause a bottleneck.
I just wish there was some simple, not too expensive, hardware device with 2-3 ports which could be used for this purpose.
One underlying concern with the routing option is how the other routers on the network will find out about this new subnet. Would this happen through some automatic routing discovery protocol? Can this be done by just tick a RIP tick box somewhere? Even though I think our routers use a new protocol than this.
Sorry this is turned out to be very long.
Any advice much appreciated! ;)