This guide demonstrates how to plan and subnet an office network for ~150 client PCs and various infrastructure devices using IPv4 subnetting. The goal is to segment the network for better performance, security, and management.
| Device Category |
Quantity (Approx.) |
| Client PCs |
150 |
| Servers (internal use) |
5 |
| NAS |
1–2 |
| IP Cameras (CCTV) |
16–32 |
| Printers |
5–10 |
| Wireless Access Points |
3–5 |
| Networking Devices (Routers/Switches/Firewalls) |
3–5 |
| Reserved (future expansion) |
~20 |
Estimated Total Devices: ~220+
- Use Private IPv4 (Class C):
192.168.X.X
- Organize network by function or department
- Allow easy monitoring, security rules, and access control
- Allocate enough IPs per subnet with room for future growth
| Subnet Name |
CIDR |
IP Range |
Hosts Available |
Assigned Devices |
| Clients |
192.168.10.0/24 |
192.168.10.1 – 192.168.10.254 |
254 |
150+ client PCs |
| Servers |
192.168.20.0/28 |
192.168.20.1 – 192.168.20.14 |
14 |
5 servers, UPS, admin access |
| NAS/Storage |
192.168.30.0/29 |
192.168.30.1 – 192.168.30.6 |
6 |
NAS, backup appliances |
| CCTV Cameras |
192.168.40.0/26 |
192.168.40.1 – 192.168.40.62 |
62 |
Up to 32 IP cameras |
| Printers |
192.168.50.0/27 |
192.168.50.1 – 192.168.50.30 |
30 |
Network printers |
| Wi-Fi / APs |
192.168.60.0/28 |
192.168.60.1 – 192.168.60.14 |
14 |
Wireless APs and guests |
| Network Infra |
192.168.70.0/28 |
192.168.70.1 – 192.168.70.14 |
14 |
Routers, firewalls, switches |
| Reserved |
192.168.100.0/24 |
192.168.100.1 – 192.168.100.254 |
254 |
Future expansion |
- Use VLANs to isolate subnets and apply firewall rules.
- Assign static IPs to servers, printers, cameras, and networking devices.
- Use DHCP for dynamic allocation in the client subnet only.
- Reserve
.1 in each subnet for the gateway (router).
- Use
.254 in each subnet for the management interface (e.g., SNMP/NMS).
| Subnet |
Access Policy Example |
| Clients |
Internet, internal servers only (via ACL) |
| Servers |
Isolated, accessible from IT/Admin IPs only |
| Cameras |
No internet access, access from NVR only |
| Printers |
Access allowed from clients, deny from guests |
| APs/Wi-Fi |
Separate VLAN for guest vs. internal users |
| Infra Devices |
SSH/Web UI only from admin IPs |
/24 subnet provides 254 usable IPs – perfect for large client blocks./26, /27, /28, and /29 minimize wasted IPs for smaller device groups.- Separation improves security, makes troubleshooting easier, and allows network growth.
| Total Subnets Used |
8 |
| Address Space Used |
192.168.10.0 – 192.168.100.254 |
| Main Protocol |
IPv4 (Private Class C) |
| Isolation Method |
VLANs + Subnets + ACLs |
🛠️ A well-planned subnet structure helps improve performance, scalability, and security in any office network environment.