New network - IP addressing

[CHiLL]

Hello,

I'd like to start this thread by stating that my networking and subnetting knowledge isn't exactly brilliant! This isn't a knock against anybody or any decisions made, I'm just trying to get a better grasp of the situation! I guess my knowledge is all based around the old class based networking. All the schools I've worked in previously have been on class C networks (192.x.x.x or 172.x.x.x). Currently, this school's network is on the 10.122.76.x.x range using a 255.255.252.0 subnet with no VLANs, so its one big flat network.

 

We are completely ripping out the old network and having a new infrastructure installed, as well as new server and client hardware. We have brought in a company to manage and implement this for us and they've recommended the IP addressing scheme to use, but I'm struggling to wrap my head around it.

 

They have recommended remaining on the 10.122.76.x.x rang using 255.255.252.0 as the subnet, but then introducing VLANs to segregate the clients.

 

I'm wondering why they've recommended that network range, as the class based 192.168.x.x range makes more sense to me personally, or rather I find it easier to understand.

Edited June 25, 2015 by CHiLL

[plexer]

10.0.0.0 is a Class A private address range and is the one I see more of in businesses rather than 192.168.x.x

 

Ben

[Boredguy]

When the Regional Broadband Consortiums started up 16 years ago, all of the schools were assigned a 10.x.x.x range by the ISPs.

 

192 is fine for your own personal networks, but when the RBC's were formed the idea was all the schools were part of 1 large network, which required the 10.x range to ensure they had sufficient addresses to assign to each school. Secondary's normally had 1024 allocated addresses and primary's 255. These days you can choose to move away from the 10 range if you have an alternative ISP.

[FN-GM]

172.x is a class B network BTW

 

You have more space to work with on a class A system. On a class C network the maximum number of hosts on a subnet is 254.

 

Are you connected to an LA? If so you may have to keep within the 10.112.76.0 /22 subnet.

[Steve21]

Is it a small network? Like primary/junior?

 

From those IP addresses it sounds more like it's your public IP ranges, not a private setup. (As in like grid assigned ones). If it was real private it would normally be a logical range like 10.0.x.x 10.10.x.x 10.20.x.x

 

Steve

[CHiLL]

Thanks for the replies.

The IP address range was provided by the council from what I gather, so I'm wondering why this company we've got in have decided to stay on that network. I don't think we are obliged to keep our clients on that address range, but just have routing set up so that our internal traffic (if on a 192 network for example) can get out to the council's network/Internet.

 

We are a fairly small network in secondary school terms. We have approximately 300-400 clients, both wired and wireless across the site.

Edited June 25, 2015 by CHiLL

[FN-GM]

Is it a small network? Like primary/junior?

 

From those IP addresses it sounds more like it's your public IP ranges, not a private setup. (As in like grid assigned ones). If it was real private it would normally be a logical range like 10.0.x.x 10.10.x.x 10.20.x.x

 

Steve

 

The class A range he gave is in the private range.

 

10.0.0.0 - 10.255.255.255.

 

- - - Updated - - -

 

Thanks for the replies.

The IP address range was provided by the council from what I gather, so I'm wondering why this company we've got in have decided to stay on that network. I don't think we are obliged to keep our clients on that address range, but just have routing set up so that our internal traffic (if on a 192 network for example) can get out to the council's network/Internet.

 

That's why they have stuck with 10.112.76.0 /22 if you go outside of this you won't be able to route to the council / internet.

 

How many subnets have they chunked (sub netted) it into?

[Steve21]

The class A range he gave is in the private range.

 

10.0.0.0 - 10.255.255.255.

 

Yes but there's "his" private and there's "Grids/LEA" private as I said

 

- Edit - As in if it was NAT'd you wouldn't pick that range starting so far up (well you could but you know)

 

Steve

Edited June 25, 2015 by Steve21

[CHiLL]

The class A range he gave is in the private range.

 

10.0.0.0 - 10.255.255.255.

I know its in the private range, but when I learnt about IP addressing all those years ago, class A addresses were used by the massive organisations with like millions of clients!

 

Yes but there's "his" private and there's "Grids/LEA" private as I said

 

- Edit - As in if it was NAT'd you wouldn't pick that range starting so far up (well you could but you know)

 

Steve

I don't understand how previous schools have been on Class C networks and been able to get their traffic out across their councils network which has been on a Class A network.

[Steve21]

- - - Updated - - -

I know its in the private range, but when I learnt about IP addressing all those years ago, class A addresses were used by the massive organisations with like millions of clients!

 

 

I don't understand how previous schools have been on Class C networks and been able to get their traffic out across their councils network which has been on a Class A network.

 

Normally you have a NAT device (e.g. ISA/TMG/Firewall) that effectively puts you behind another set of IPs and does the work to map between them. Else if you map one IP to one device you'll run out when you hit your limit of "GRID-Private" IP addresess.

 

As an example:

 

We have our 8 Public IP addresses

Our Grid Private Range of a few hundred

And then our Private 9999999milllllion behind our NAT

 

Steve

Edited June 25, 2015 by Steve21

[FN-GM]

I know its in the private range, but when I learnt about IP addressing all those years ago, class A addresses were used by the massive organisations with like millions of clients!

 

I was talking to Steve21 that's why I quoted him.

 

 

 

I don't understand how previous schools have been on Class C networks and been able to get their traffic out across their councils network which has been on a Class A network.

 

The routing must be different for them schools. In theory you can use any range providing another school hasn't used it. But getting the LA to allow you to pick your own range is another issue. Whats the problem anyway? I can't see anything wrong with the Class A range the company want to use.

 

You could NAT it if you want to use another range.

Edited June 25, 2015 by FN-GM

[Boredguy]

It depends on how the internet gateway was configured. We have a 10.x.x.x range like everyone on the SWGfL, but we use a 172.x.x.x range for our BYoD and do internal NAT, but it does mean that it all hits a single proxy server upstream but ah well

[tmcd35]

My understanding is there are three private ranges, one based from class A (10.), one based from class B (172.x.) and one based from class C (192.168.). Which one you use is completely arbitrary so long as you have enough IP's for your requirements. The actual class of the network is defined by the subnet mask not the base IP. So 10.122.76.0 range using 255.255.252.0 is actually a class C network. The only thing that is important is you have enough IP's and all assigned IPs full within the subnet mask.

[FN-GM]

So 10.122.76.0 range using 255.255.252.0 is actually a class C network. The only thing that is important is you have enough IP's and all assigned IPs full within the subnet mask.

 

You need 24 bits or more for a Class C. This has 22. Either way the class means nothing anymore since the days of Classless.

[CHiLL]

The routing must be different for them schools. In theory you can use any range providing another school hasn't used it. But getting the LA to allow you to pick your own range is another issue. Whats the problem anyway? I can't see anything wrong with the Class A range the company want to use.

I don't think there's a problem as such, I'm just wondering why they decided that 10.122.76.0/22 was the way to go over other network ranges. Like I mentioned, subnetting isn't a strong point of mine, so I'm just trying to figure out how it will all work.

 

It depends on how the internet gateway was configured. We have a 10.x.x.x range like everyone on the SWGfL, but we use a 172.x.x.x range for our BYoD and do internal NAT, but it does mean that it all hits a single proxy server upstream but ah well

I know that the company will be implementing a Cisco ASA, though I'm currently not too sure what that will do.

[tmcd35]

You need 24 bits or more for a Class C. This has 22. Either way the class means nothing anymore since the days of Classless.

 

Relised my mistake after I posted - that would be a class B network

[Steve21]

I don't think there's a problem as such, I'm just wondering why they decided that 10.122.76.0/22 was the way to go over other network ranges.

 

Sounds like lazyness tbh Don't need to install NATing or sort routing etc. But you could get yourself into issues if you run out of IP addresses if you do that, and then would need to re-do it all again anyway.

 

Steve

[ITGuyWestMidlands]

192.168 is often the default for mant network devices. Going with 10.0.0.0 prevents any hard to find ip conflicts when the fevices suddenly start to reset to their defaults. Im also told 192.168 can alse give you problems with external vpn access. Id go with 10.0 personally.