Networking question - Experts, please help me out with this...

[ShavedLebaneseBear]

I am moving some PCs to a new subnet. I recieved the IP info already, but I am a bit confused about what I have been given.
The info is as follows:

I was given the subnet in this form --> xxx.xx.xx.xx/xx

I will have a pool of 14 DHCP addresses and one static address. I am thinking the static address is for the router.

My 2 questions are:

1. The subnet I was given (above) has a slash after the last octet, with another 2 digit number coming after it (xxx.xx.xx.xx/xx.)
What is the slash for and what does that last 2 digit number represent? I am only familiar with a standard IP address without a "5th octet."

2. We normally do not use DHCP here, only static IP addresses. If we were given the static subnet above, how would we be able to use DHCP? I thought you could only use one or the other, and this scenario looks like it uses both. Could the router here have already been configured to distribute our own range of public addresses through DHCP? Or is that even possible?
The only router experience I have really had is with standard home routers that distribute private IP addresses, like 192.168.x.x , through DHCP.

Thanks for the help!

[Deadbent]

Okay, gonna need to re-read #2 a little bit for some advice, but as far as number 1...This I can recall :p

This is a perfect example of CIDR. Classless interdomain routing.
Real greaseball shit to me, but its the way things work.
It's pretty much the way ip addresses are deciphered, and located, etc.
A lot of this shit isn't seen too often too, because private networks in homes and a lot of smaller businesses and what not, usually are routed in another fashion with diff address styles. (mostly like dhcp, which is what I'm used to too)

Basically....
Whatever comes after the slash is the amount of bits used in both the subnet and net. Almost like just a way to define IP's. That's all. So like... xxx.xxx.x.x/6, means the first 6 bits are where the address is.

It's different if you've got you've got multiple bits for the subnets though I think.
So becareful. (and this part I don't want to confuse about, so take it with a grain of salt)
The amount of subnets are added to the amount of bits....
So the address above would be xxx.xxx.x.x/8. if you've got two bits...etc.

If that's even making sense. It's hard to give example without visual aid.
I probably sound like a goon.
But I'll go grab a book and see if I can give you a better example of 1, while figuring out 2.
Meanwhile google up on Cidr.

(Part two, is definitely giving you problem due to the greaseball nature of cidr.. hopefully we can solve this problem in short order. I'll be back in a few)

[Fendbass22]

The only thing I can think on number two is that they want you to use the router which will be at the static IP, to assign the 14 DHCP addresses. Which, commercial grade routers should be able to do.

Do the 14 addresses need to be seen by the public?

[Deadbent]

Yeah,
the address is to the router, and the digits after the slash indicate what the ips should be attached to it. At least thats what it sounds like.
And it does sound like they've been previously mapped out.

[Deadbent]

Any updates or progress J7?

[ShavedLebaneseBear]

Well, it seems that the xx after the slash should have a "0" in front of it normally (xxx.xx.xx.xx\0xx). I was told that the number after the slash indicates the amount of addresses that were issued. The number somehow relates to the subnet IP, and defines the total amount of addresses that will be used...almost like a "percentage", maybe?

As for the DHCP issue, we are trying to find out why we are using DHCP in this scenario, since we always have used static before. If we are forced to use DHCP, then we are going to have to register MAC addresses. DHCP is going to make it difficult for the remote users, since the DNS tables have not been flushed in a long time.

The unfortunate part of all of this, is that we are not the only IT group here, so we have to depend on others in order to get stuff like this done.

[yellowstonesteve]

192.168.0.0/24 the /24 means it's a 24 bit subnet mask, which would be the standard 255.255.255.0
you need a subnet calculator try this http://www.subnet-calculator.com/you can use the /## to see what the subnet would be.