How to Join use morethan 250 IP in the same network?

I am new to the network.
I just install Windows Server 2008 R2, DNS and DHCP.
Now I have 500 clients, and all client need to have a local static IP (192.168....).
my default gateway is

Now I got the problem thatI can only assign to So I have about 250 clients left.
What should I do?
I want them to be in the same network.

Pls help.
Who is Participating?
Lee W, MVPTechnology and Business Process AdvisorCommented:
Is this a homework question?  How do you suddenly have 250 more machines?

Why don't you use a Layer 3 switch and setup two or more subnets?

If you explain further we can help you.  But we CANNOT do your homework for you and the question as I read it sounds like homework.  If it is, explain what YOU think you'd do and we can help you understand if you're right or wrong, but we CANNOT do it for you.
JimmyStarAuthor Commented:
No, It's not a home work.
I'm in the Developer Team, and now I tried to test my application in the 500 VMs.
My knowledge in networking is very limit, so that's why i came here to ask.

I never thinking about the more than 250 IP, not i happen. :-(

I run 50 Servers with 10 VMs in each server = 500 VMs. that that will need 500 IPs.
I want to access to all VM through Remote Desktop within the same network. and All VMs need to be accessible to the internet for update the application only.
Lee W, MVPTechnology and Business Process AdvisorCommented:
Change the subnet mask to  That should give you 510 usable addresses between through
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JimmyStarAuthor Commented:
So that mean I can use them in the same rank of default gateway ?

I have tried to change it, and it seems not working ( it cannot access to the internet or other ).
Lee W, MVPTechnology and Business Process AdvisorCommented:
Did you set the gateway to have the same subnet mask?  EVERYTHING in the 192.168.1 and 192.168.0 networks must have the same subnet mask.
JimmyStarAuthor Commented:
You mean, I need to change the subnetmask on the router to .54?
I have changed that, but it still cannot access to the internet. Do I need to do anything with DHCP?
JimmyStarAuthor Commented:
I heard people say about VLAN. So if we do VLAN that mean we can get more IP to use?
Lee W, MVPTechnology and Business Process AdvisorCommented:
Unless you have a Layer 3 switch, you need a router between the VLANs.

What did you do when I told you to change the subnet mask?  Didn't you change it DHCP?  WHERE did you change it?
JimmyStarAuthor Commented:
What I did is, I change the subnet mask on all clients. and also change the subnet mask on the router. all to 254

That's it.
Lee W, MVPTechnology and Business Process AdvisorCommented:
what on the router did you change?  Without a clear diagram of what you have, you may have changed the wrong thing.  Would be best if you could post screen shots of what you have.

As for changing DHCP, if your clients are using DHCP, then they shouldn't have a subnet mask defined statically and you'd have nothing to change EXCEPT in DHCP (and the router).  So I don't know how you're using DHCP AND setting the client's subnet mask.  

A diagram and screenshots would be great and help a lot in ensuring we have the correct understanding of things.
Leew is right. You need to only change the subnet mask on the router interface and on the DHCP server but putting your VM's IP Config setting to automatically acquire their IP Configs from the DHCP Server. The DNS Server's IP Configs  subnet mask must be statically set to If you are using NAT for Internet connectivity then you need to check your ACL to reflect that it too has responded to the new subnet mask.

If you want you can use this private network address, that will give you lots of IP addresses. You can further subnet it if you want.
You mean from to right. On your clients, the Gateway is still even on the clients with an 192.168.2.x IP Address.

VLAN is needed to split physical networks in smaller pieces without the need of buying additional hardware (of course, switches must be VLAN Ready). VLAN act like separate networks, they don't see each other. This means you need a Router or Switch with L3 Support to let this Newtorks talk to each other.
Yes the gateway remains . For VMs I dont think there is no need for buying and additional router or L3 Switch.

With a network of the number of IPs that he needs will be met without having the 192.168.2.x IPs.

I don't know if this was already answer but here is my contribution:

First, you should never have your DHCP starting at the same point your "GATEWAY" or any server you may have (SERVERS NEED STATIC IP) unless you have created ranges to be excluded from the scope.

Now, you have to options here because you can't have more than 1 subnet on a scope but you can have more than 1 in a superscope.

The big difference between them is the possibility to have a gateway per scope but if you know you will have only one you can go create a superscope.

You must first stop/turn off your DHCP server actual scope (if exist) and I will recommend to delete it and create a new one.

When creating the new scope enter your start IP Address with and your End IP address with something like (this should give you plenty or room for your clients, server, printers, etc.) at this point you can choose the length of your subnet mask or enter it manually here you can enter 23 for the length or after that just fill in the rest of the information (DNS servers) and do not activate the scope yet do your exclusions first (servers, printers, etc) then activate the superscope.

The only thing now should be to change your STATICS IPs (Servers, printer, Gateway, etc) netmask to match the scope on the DHCP server.  You can manually test this using a laptop or mobile by changing your IP to any on the scope to see if you get access to internet.

Good Luck!
You can also use a larger subnet. For instance, with a netmask of
Or even
This would be more common, since 192.168.x.x are usually used as Class C networks.

Now, you must make sure that the default gateway is in the same subnet for ALL THE nodes (VMs) that need to route packets through the gateway.
This is very basic TCP/IP config, I suggest that you read some documentation about it

Using a DHCP server is much better than assigning manually 500 static IP addresses to your nodes.

But you must also be aware that a density of 500 VMs (with 500 virtual disks, 500 Virtual CPUs etc) will be hard to achieve unless you have very powerful and usually very expensive ESX hosts (assuming you are using VMWare ESX). ANd you just cannot boot 500 VMs simultaneously, you must "stage boot"...

Maybe another kind of simulation would be better than 500 actual VMs ?
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