Extending DHCP

Sure. Make sure to check routes on routers and such as you are moving to a new network all together. If you have servers make sure to change their masks.

Before you were on network 192.168.1.host which meant that anything starting with 192.168.1was on the same network. Now anything that just starts with 192.168 will all be on the same network. You'll have like 65,000+ node possibilities

No. 192.168.X.X is still a class C network, and as such the largest netmask you can use it 255.255.255.0. If you want to maintain all of your hosts on the same network you will have to use a class B, which is 172.16.X.X through 172.31.X.X and a large netmask of 255.255.0.0. See RFC 1918 for other info on private network numbers and RFC 950 for subnetting.

Instead of changing the subnet mask, I would recommend simply adding another subnet for your phones. You could use 192.168.2.x and add this network and range to your DHCP server. I think it would simplify administration of the devices to keep themseparate from your regular data network. As you said, the 253 addresses available to you from 192.168.1.x are enough for your data devices. How many folks are going to have more than one IP phone? If you want give yourself more room, consider an address range where you can use a 23 bit mask instead of 24. That gives you two class C address spaces, but means you have to find two subnets adjacent to each other. There are a number of freebie IP subnet calculators out there that can help you find the start and stop addresses. Hope this helps. Best wishes,
- ck

Answer 2 is entirely wrong. You CAN use 255.255.0.0 subnet mask for 192.168.1.x series of address. In classical network terms its called VLSM/CIDR.

However, Answer 3 seems to be the best possible solution for you. Creating another range of DHCP pool as 192.168.2.x 255.255.255.0 will server your purposes easily and will also help in the administration.

This question was auto closed due to inactivity