Five mistakes I see in small-office networks (and how to fix them)

Small offices rarely have a full-time network engineer, so the same problems appear again and again. None of them need expensive equipment to fix.

1. Everything on one flat network

Staff laptops, guest phones, printers and CCTV cameras all share one subnet. One infected device can see everything. Fix: separate them with VLANs and allow only the traffic each group needs.

2. Default passwords on network devices

Routers, switches, NVRs and printers still use the password from the box. Fix: change every default, store the new ones in a password manager, and turn off management from the internet. The switch hardening playbook is a good checklist.

3. No documentation

Nobody knows which port goes where, which IP is the printer, or who has the admin password. Fix: one simple spreadsheet: device, IP, location, port, owner, last updated. Label both ends of every cable.

4. Firmware that's years old

Old firmware means known security holes. Fix: check for updates every quarter and plan a short maintenance window. Always back up the configuration first.

5. "Temporary" fixes that stay forever

A small unmanaged switch under a desk, a cable across the floor, a static IP typed in "just for today". Fix: keep a list of temporary changes with a date to remove them, and actually review it.

Start with the cheapest win: change default passwords this week. It takes an afternoon and closes one of the most common doors attackers use.