Number of IP addresses available- network newbie(ish)

[rocknrollstar]

Hi, we have a win2k network with xp pro clients. Although I didn't setup the network or server originally, I do try and maintain it in my spare time (I'm a full class teacher the rest of the time).

We had some issues with IP conflicts with some printers, and I am looking into dhcp reservations, which looks fine. However, in oder to try and organise the IP layout, I was wondering how many ip addresses are available for our network?

The DHCP scope is as follows:
Start: 10.199.224.100
End: 10.199.224.254
Subnet: 255.255.248.0 (length 21)

Am I right in saying that we have 154 IP addresses available? Don't think so, but not sure how to work it out. We haven't go that many pieces of networked equipment yet, but I'm sure it won't be long.

Many thanks for your help.

[IrritableTech]

You have 154 addresses available in your scope which can be assigned by you DHCP server to devices, however the subnetmask suggests you have a usable range of 10.199.224.1 - 10.199.231.254 or 2046 addresses.

[mattx]

Online IP Subnet Calculator

Always handy......

[tmcd35]

According to a nifty little calculator on my iPhone (too lazy to work it out for my self). Your network should be as follows:

Network: 10.199.224.0
Broadcast: 10.199.231.255
Subnet: 255.255.248.0
Available IP's: 2046 (10.199.224.1 - 10.199.231.254)

Are these IP's internally assigned, or does your ISP/LA give you a range of IP to use. Here in Norfolk our LA gives us a range of IP's (mines 10.96.22.0/255.255.254.0). If they are assigned to by your LA/ISP it may be worth asking them what's been assigned.

[rocknrollstar]

Great, thanks everyone for your quick replies.

Does that mean that I can assign an ip address of, say, 10.199.231.100 to a printer, and this will work on the network? I take it the gateway would all still stay the same?

Thanks.

[eduabncs]

Great, thanks everyone for your quick replies.

Does that mean that I can assign an ip address of, say, 10.199.231.100 to a printer, and this will work on the network? I take it the gateway would all still stay the same?

Thanks.

In thorey yes. However as others have said check with your ISP/RBC/LA as to how they have segmented their network and what the range made available to you is. They should give you your start and finish IP address at either end of your range.

Essentially though on a 255.255.248.0 subnet you have 8 host subnets 10.199.224.0 through to 10.199.231.254 in your case. Each host subnet has 254 IP address available.

Good IP allocation is essential for network management, here on the BGfL we recommend schools use the following plan (ammended as circumstances require) BGfL School Network Standards

[Michael]

The DHCP scope is as follows:
Start: 10.199.224.100
End: 10.199.224.254
Subnet: 255.255.248.0 (length 21)

You actually have more than 154. The DHCP scope starts at 100 to 254, but this just means 1 - 99 isn't available for DHCP to allocate.

This means your primary server could be: IP_10.199.224.5x

Your printers could be: IP_10.199.224.6x

And your access points could be: IP_10.199.224.7x

This is how I usually do things and it means you don't need to setup reservations. You can set the printer as: IP_10.199.224.61 (for example), as DHCP will only allocate or use IPs 100 to 254 for computers themselves.

[rocknrollstar]

Awesome, thanks for your replies. Extremely helpful- I did quite a few searches on trying to figure this out, but none as clear as these responses

eduabancs, I couldn't access the page for "BGfL School Network Standards" as it was restricted. Any change that you could send it over to me?

Regards.