Solved

TCP/IP subnet question

Posted on 2014-02-09
5
569 Views
Last Modified: 2014-03-03
My network is growing.  I am using dhcp and I have almost used all the available host ip addresses.
Everyone has a wifi need on their cellphones and it is adding up quickly.
I need to be able to have dhcp add more than the 254 and still be on my network.
How do I set up the subnet to handle that?
I am currently using 192.168.1.1 - .254 and the router is on 1.1
0
Comment
Question by:KentBaldwin
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
5 Comments
 
LVL 10

Accepted Solution

by:
Korbus earned 500 total points
ID: 39845709
The simplest solution would be to expand your subnet mask by a single byte.

Use 192.168.1.1 - 192.168.254.254
You subnet mask would become simply
255.255.0.0

This will give you (aprox) 256*256 total IP addresses you can assign.

You could alternatively expand by only a single bit, which would double your number of available addresses:
Use 192.168.1.1 -192.168.2.254
SNM: 255.255.254.0


Once you make the subnet changes to all the statically-addressed computers, you'll change your DHCP scopes to match it.

Be careful though,  too many devices on the same subnet can hinder network performance.  If this starts happening, you may need to consider breaking your network into separate subnets (one for wifi devices, one for wired workstations and server, for example)
0
 
LVL 53

Expert Comment

by:strung
ID: 39845725
I am not sure that is right. My understanding is the Class C 192.168.x.x series of addresses have a maximum of 256 addresses in a subnet. For larger number of addresses, you are supposed to use the Class A or B addresses:

10.0.0.0 - 10.255.255.255
or
172.16.0.0 - 172.31.255.255

See:  http://en.wikipedia.org/wiki/Private_network

and

http://www.cse.uconn.edu/~vcb5043/MISC/IP%20Intranet.html
0
 
LVL 26

Expert Comment

by:Fred Marshall
ID: 39845804
I believe that "Class C", etc. is an anachronism.  Best not think that way.

The private range of addresses that you are using is within:
192.168.0.0/16.

I wouldn't go to that extent however.
I would likely change the network address to 192.168.0.0/23 or 255.255.254.0 .
This will double the number of addresses while keeping the current addresses intact to a point - in that 192.168.1.0 to 192.168.1.254 are all viable addresses within 192.168.0.0/23.

So, if you have a printer with 192.168.1.2/24 then you could change that to 192.168.1.2/23 (or 255.255.254.0) on the printer but any computers pointing to that address would not need to be changed.  Well, except their own subnet mask would be changed of course to 255.255.254.0 but not the printer setup.  Just an example.....

During the transition you may find that everything works pretty well anyway before all the subnet masks are changed.  That can ease transition and is better than a wholesale change of the address range.  The process should start with the DHCP server's own subnet mask and the DHCP lease subnet mask and go from there giving highest priority to the core devices.
0
 
LVL 83

Expert Comment

by:Dave Baldwin
ID: 39845809
That "Class C" information is the "old way" of doing it.  The remarks about changing the network mask and DHCP range are correct and would apply even to the other private IP ranges you mentioned.  While the term "Class C" is still used in many places, it is not a technical method.  Classless Inter-Domain Routing (CIDR) was introduced in 1993 to make better use of the IP address space.  This page http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing has a chart that shows how to do subnetting or "IPv4 CIDR blocks".
0
 
LVL 16

Expert Comment

by:vivigatt
ID: 39847782
You can perfectly expand your existing DHCP range/scope with a change in the subnet.

Check these resources:
http://support.microsoft.com/kb/255999

and

http://www.subnet-calculator.com/
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Do you come here a lot? Are you lazy like me and don't want to go through the "trouble" of having to click your Dock's Safari icon and then having to click your Experts Exchange Favorites bookmark to get here? Well then this article is for you.
Citrix XenApp, Internet Explorer 11 set to Enterprise Mode and using central hosted sites.xml file.
This Micro Tutorial will demonstrate how to add subdomains to your content reports. This can be very importing in having a site with multiple subdomains.
Shows how to create a shortcut to site-search Experts Exchange using Google in the Chrome browser. This eliminates the need to type out site:experts-exchange.com whenever you want to search the site. Launch the Search Engine Menu: In chrome, via you…

738 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question