Most smart home security articles tell you to “change the default password” and call it a day. That is step one of twenty. Here is what actually protects your network when you have 50 connected devices.
Network Segmentation
IoT devices on their own VLAN, firewalled from your main network. If a cheap smart plug gets compromised (and some have been), it cannot reach your laptop, NAS, or anything else important. This is the single most effective security measure for a smart home.
Local-Only Devices
Every cloud connection is an attack surface. Devices that work locally (Zigbee, Z-Wave, local-only WiFi devices flashed with ESPHome or Tasmota) cannot be hacked through their cloud servers because there are no cloud servers. My Zigbee sensors have zero internet access and work perfectly.
Firmware Updates
I check for firmware updates monthly. Home Assistant makes this easy – it flags devices with available updates. Outdated firmware is how most IoT devices get compromised. If a device stops getting updates from the manufacturer, replace it.
DNS Filtering
I run AdGuard Home on my network. It blocks telemetry, ads, and known malicious domains at the DNS level. Some IoT devices phone home to suspicious servers – DNS filtering lets me see exactly where each device is trying to connect and block anything I do not trust.