Outgrowing a /24 network

Question

We have outgrown our 192.168.1.0/24 network. We are ready to replace the router so I thought this would be a good time to expand the network. I've configured plenty of /24 networks but never anything bigger. My first thought was to go with a 10.11.0.0/16. Then I could do stuff like 10.11.1.1-254 DHCP for workstations, 10.11.2.1-254 for servers, 10.11.3.1-254 for printers etc. I imaging this would work but I'd have most of the 3rd octet unused.

I suppose a better way to do this would be a 10.11.0.0/23. Then I'd do 10.11.0.1-255 DHCP for workstations, 10.11.1.1 - 10.11.1.20 for servers, 10.11.1.21 - 10.11.1.40 for printers etc. Now my hosts would only be 2*256 but still plenty of room.

Am I on the right track or way off?

Answer 1

You can use any subnet from the RFC 1918 ranges - 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8 - with any subnetting, including 192.168.2.0/23, 10.111.220.0/22, and 172.16.24.0/21.

I'd recommend using at most a /23 prefix - larger than that should be subnetted and routed in between (e.g. with a decent L3 switch).

While you're reorganizing your network, you should consider defining multiple security zones, each consisting of one of more IP subnets/VLANs. The router(s) in between allow you to control traffic between zones, as required by your security needs.