Currently there is a DHCP (Windows 2008 R2) server with a scope. The initial scope ip address of 10.1.1.0 - 10.1.1.254, no part excluded. Subnet mask of 255.255.255.0. There are four gateways.They run out of available IP addresses.
How can I increase the number of available IP addresses?
Should I buy a new scope 10.1.2.0-10.1.2.254 up? How will they see each other?
Or change the subnet mask 255.255.254.0 and change the current scope 10.1.0.0 - 10.1.1.254?

Thanks for helping their response!

Peter Parta

Or change the subnet mask 255.255.254.0 and change the current scope 10.1.0.0 - 10.1.1.254?

Yes, you'll likely need to back off the subnet mask.

 http://www.subnet-calculator.com/

You will need to back the subnet like Dave's told, but if you got 4 gateway, you might target which part you enlarge, as you will have to modify all router and subnet on all gear.

For the DHCP's change you can follow that article; How to Easily change a DHCP's Scope Subnet

Hi Peter,

Agree with Dave and Yagmoth.

Besides, if you want to add a new scope, we also need add routes on router for different subnets.

Best Regards,

Leo