Migrating 192.168.0.0/16 to 10.0.0.0/8

hardware_failure

hardware_failure

[H]ard|Gawd
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Mar 21, 2008
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Im helping a client whos running out of private IP's to find a solution.

Rather than buying additional routers, I was thinking about helping them setting up a 10.0.0.0/8 network.

Ive played with a few class A networks, but never built one from the ground up. Does anyone have any suggestions for good resources to research basic class A networking?

Thanks.
 
Im sure this will be the first of a few posts to say something to this effect....

Are you kidding me? :rolleyes::rolleyes::rolleyes::rolleyes::rolleyes:

Dude, you're telling me that you manage a client with 65K hosts/devices on their network and you're asking for basic class A networking documentation? Please don't tell me that they have a completely flat network, do you know what I mean when I say that?

um.... idk even know what to say, lol :p Buying additional routers also wouldn't help out your addressing solution.
 
man...if this is true thats a damn good client to have :) 65k ip's assigned? thats god damn crazy!
 
My advice, subnet, lots of subnets. Divide that network into many broadcast domains.
 
Consider the easy solution of creating another network and routing between the two
 
* braces for impact *

192.168.0.0/16 can have 65k IP's but thats spanned across 256 networks. Im looking for a single network with more than 254 IP's.
 
Is there any particular reason?

Edit: I guess what I'm getting at is that there are other options to the get networks to communicate besides switching to a different IP address scheme.
 
okay first off I mislabeled the network - its a typical /24. (not /18)

Basically what Im looking for is more than 254 ips without having to buy extra routing gear for vlans n stuff.
 
You can set up a windows box to route also, would probably be the easiest solution.

I don't have any resources for setting up a class A network, but you can also use the 172.16.0.0-172.31.255.255 network for more simplicity.

Edit: I you have a sufficiently fancy router you could probably have it handle a second network too.
 
hardware_failure said:
* braces for impact *

192.168.0.0/16 can have 65k IP's but thats spanned across 256 networks. Im looking for a single network with more than 254 IP's.
Click to expand...

Um no, 192.168.0.0/16 has is one flat(classful, hence class B) network with 65K hosts. If you begin to subnet this classful network into say /17, /18 then this becomes sub networking and will span multiple networks.

If you are looking for a single device that will give you more than a class C range to work with you're pretty much leaving the realm of low end SOHO gear(I think, im not used to that stuff). Perhaps a UTM or lower end Cisco router.
 
hardware_failure said:
* braces for impact *

192.168.0.0/16 can have 65k IP's but thats spanned across 256 networks. Im looking for a single network with more than 254 IP's.
Click to expand...

You need to be more specific. Exactly how many addresses do you need? Find that, which I'm sure isn't more than a few hundred, then give yourself some breathing room. Something like 10.0.0.0/23 would give you from 10.0.0.1 to 10.0.1.254 as usable addresses. That's 510 addresses.
 
why not just change the mask on the router from /24 to /23 or /22

maybe make your DHCP scope a bit bigger...

done and done...

keep the addresses the same....
 
goodcooper said:
why not just change the mask on the router from /24 to /23 or /22

maybe make your DHCP scope a bit bigger...

done and done...

keep the addresses the same....
Click to expand...

I second this motion...

But you would need to do it on all devices not just the router.

But bear in mind that a network this large generates a lot of unnecessary broadcast traffic.

I rescind my motion and recommend creating a second subnet or vlan and routing traffic as needed.

My network is not large (around 50 PCs) but I have separate subnets for my servers, workstations, wireless, IP phones and a Guest access.
 
it is very easy to do it on all devices, you just change it in your DHCP server, unplug your switches.... then plug them in again :D


or reboot :D
 
hardware_failure said:
* braces for impact *

192.168.0.0/16 can have 65k IP's but thats spanned across 256 networks. Im looking for a single network with more than 254 IP's.
Click to expand...

Having more than 254 nodes on a single subnet is asking for organizational hell, and much more potential for a network outage.

What type of networking equipment do you currently have, and why not look into separating them out instead of just increasing the problem?

I run a network of about 300 pc's split into 14 different networks (1 for each location) i couldn't imagine having all those Pc's in one location and all on the same subnet...I would probably commit Hari-Kari
 
Agreeing with setting up a separate network; /24 is as high as I'd go due simply to broadcast traffic. Further, if you keep the network segmented, then you limit the damage when things go wrong ( like switch dies, or you get a chatty nic ).
 
personally, it all depends on the topology... i mean if you have a dead switch, you're going to lose that many users anyway.... (esp if using vlans)

if you've run out of 254 addresses, you've got a crapload of switches already... and your main switch should definitely be enterprise grade, and probably good idea if it is redundant as well...

the chatty nic is like the only thing that could actually bring down your subnet, and how often does that really happen? if you keep your boxes clean (viruswise) then the chances of that happening are REALLY slim... i've only had it happen a few times in a course of 4 or 5 years of troubleshooting downed networks...

but like i said, all depends on the topology.... i agree that more than 250 devices on 1 subnet seems like a lot, but it depends on what is going on... what is using the addresses, and what the traffic will look like
 
I've had /16 networks with oh 300-400 hosts and never had a broadcast problem...if he just has a little over 254 it shouldn't be a problem to use a larger subnet.
 
Can you recommend a good book on ip addressing and practical use?

Im the network admin at a growing company and want to start moving my servers, lab, engineering lab, and machine lab into separate subnets.
 
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