resubnetting question

[chipperjonesrules]

we are running out of IP addresses at a particular site, and since we will be adding some devices soon I need more IPs available.

we currently have our 2003 dhcp server handing out IP addresses with scope of 192.168.xx.xxx with subnet of 255.255.255.0

what we are thinking of doing is just changing the subnet to 255.255.252, effectively doubling the list of addresses.

from what I have read, I cannot CHANGE the current scope, but will need to delete it,and create a new one.

I have quite a few static devices, like access points and printers, will I need to change the IP settings on those systems?

I have tested a PC with the new subnet mask, and it did work find, connected to the network, so I am wondering if my static devices could be left alone?

 

[netsec50]

All device will need to be reconfigured with the new subnet mask

Chris Jessup
IT Director

http://www.network-security.co

twitter @netsecltd

 

[baddos]

I would highly recommend against a subnet that large. It would be better to create a vlan with a new subnet on that.

 

[PeterHurst]

It's a quick and dirty fix - we use 255.255.252.0 subnets for certain large groups and they are appropriate in certain circumstances.

The issues you'll have are:

Any fixed devices will have the old mask and will not be able to "see" the new devices until altered - this will include your default gateway if it's moved to the top of the range. (if you want to do this have an interim of keeping dual DG's until there's no traffic to the old IP)

You will need to create a new scope. I can't remember for sure but I think you will need to delete the old scope first.

The other thing is that using a "non natural" mask for a 192.168 may add confusion when users look at issues - printer engineers for example are likely to assume it's a typo and set 255.255.255.0. Ideally you should use chunks of 172.16.X.X but I see why you are avoiding that.

Simply put - not where you'd start from but it will work with those proviso's.