Growing Pains

I have a network that uses a 10.0.0.X with a 255.255.255.0 subnet mask. We are getting close to running out of ip addresses. When you factor in the vm hosts, vm's, switches, desktops, NAS devices, laptops, printers, and cell phones we are using about 95% of available ip addresses. We are adding 5 new employees in the fall and another 2 or 3 in the new year.

There is no plan to expand past our one office location thou we do have room to add on to our current building.

I was thinking of changing the subnet mask to 255.0.0.0 on the DHCP server and then work our way through changing the static IP addresses.

My question is does this all have to be done at once? Can we update the subnet mask on the hosts and vm's but take our time on the printers? if we do will people still be able to print?

If we change the subnet mask from 255.255.255.0 to 255.255.0.0 in theory the original ip addresses are still inside the new ip address range. Then we could organize our machines and ip address a bit more over a few days.

• static IP addresses  for servers and hosts and network equipment would stay the same - 10.0.0.x
• DHCP scope 10.0.20.x
• printers 10.0.30.x

Thoughts.... comments?