Changing DHCP to allow more than 254 ip addresses to be given out

phoenix81 used Ask the Experts™
Hi All,

We have inherited a client who have a very basic network setup consisting of a Windows 2012 Standard server which is acting as their DHCP / DNS. It is on the 192.168.100.x range.

They would like to allow over 250 users to be able to connect to the network. However as you can see their range will only allow 250 users before the DHCP leases run out.

We havent had to do anything like this before as we only look after very small companies.

Would someone mind letting me know how we can go about editing their current dhcp to allow more users to connect? can i simply change the lease range to 192.168.x.x?

The gateway is currently

Their subnet is currently

Thanks in advance for any responses
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Software Developer / Linux System Administrator / Managing Director
As I see it, its going to be a case of changing the subnet mask to allow more hosts on the network, unless you want to start managing multiple subnets and routing between them. If, for example, you change the subnet mask to, you would be able to have up to 2046 hosts and the IP ranges would be from - Naturally, this is just an example.
I believe Martyn meant a subnet mask of

Do consider whether it makes more sense to split the devices into different subnets.  That will require some further configuration but will cut down on broadcast traffic.


I see that makes sense, i will of course spin up a VM to give this a test beforehand, thank you for pointing me in the right direction both of you :)
Martyn SpencerSoftware Developer / Linux System Administrator / Managing Director

I did indeed mean and have updated my comment appropriately. @CompProbSolv Thanks for the catch! I would also point out that I typed 191.168.... and intended to write 192.168... I cannot amend the accepted answer to make this clear.

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