A private IP address is an IP address taken from a reserved range that is not routable on the public internet. The standard private ranges (defined in RFC 1918) are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Devices on these addresses can communicate within a private network, but cannot be reached directly from the internet.

In short: Private IPs are used in three main IoT contexts. Inside a LAN (the typical 192.168.1.x range home and small business networks use). Across a private APN (where an IoT SIM gives the device a private IP within the operator's network, isolating it from the public internet entirely). And across a VPN (where multiple sites share a single addressing scheme accessed via encrypted tunnels rather than the public internet).

The advantage of private IP for IoT is exposure reduction. A device with a private IP behind a private APN cannot be reached from the public internet at all. Inbound scans, brute-force attacks, and exploit attempts cannot route to the device. Outbound communications still work (the device can reach cloud platforms, management systems, and patching servers), but the device itself is invisible.

Where remote access is needed (an engineer needing to log into a router to change a configuration), it is provided over a VPN or via outbound-tunnel platforms like Teltonika RMS, both of which work over private IPs. The combination of private APN, private IP addressing, and VPN-based or platform-based remote access is the architecture pattern that most cleanly meets both operational and security requirements.