Planning an address scheme

A good address plan is boring and predictable. A bad one causes overlaps that surface years later, usually when you connect a VPN.

Start with a private range

Use RFC 1918 space: 10.0.0.0/8, 172.16.0.0/12 or 192.168.0.0/16. Avoid 192.168.0.0/24 and 192.168.1.0/24: home routers use them, so remote staff on VPN will collide with you.

Give every site a block

10.10.0.0/16   Cairo office
10.20.0.0/16   Riyadh office
10.100.0.0/16  Data centre

Divide each site by purpose

10.10.10.0/24  Staff computers
10.10.20.0/24  Phones and Wi-Fi guests
10.10.30.0/24  Printers and cameras
10.10.99.0/24  Network management

Using the third octet as the VLAN number (VLAN 10 → .10.) makes troubleshooting much easier.

Leave room

Allocate twice what you need today. Re-addressing a live network is far harder than reserving space now.