What is a static-IP IoT SIM
Quick definition
A static-IP SIM is an IoT card the carrier always assigns the same IP address to, instead of a different dynamic IP per session. It can be public (reachable from the internet) or private (reachable from your private APN or VPN). It is essential whenever a server needs to initiate the connection to the device.
When you need static IP
Three typical cases: EV chargers running OCPP that receive commands from the CPO, CCTV NVRs and IP cameras with remote access, and industrial PLCs an engineer connects to for parametrization.
Public vs private
Public: the device is visible on the internet (mind the firewall). Private: only reachable from your private APN or VPN. Private is always safer; public only when there is no alternative.
FAQ
How much does static IP cost?+
Private is often bundled in IoT plans (sometimes 1-2 EUR/SIM/month). Public is pricier: 3-15 EUR/SIM/month depending on provider.
What about dynamic DNS instead?+
If the device opens an outbound connection and holds a reverse tunnel (ngrok-style, SSH tunnel), DDNS is enough. For direct inbound from a server, static IP has no substitute.
Related terms
What is a private APN
A private APN is a mobile network access point dedicated to a single company or project. Your IoT traffic never touches the public internet: it exits the carrier straight to your data center over a private tunnel, with your own IP plan, firewall rules, and routing.
What is an IoT VPN
An IoT VPN is an encrypted tunnel between the carrier exit and the customer infrastructure. It lets devices on the cellular network reach private servers without going over the public internet. Typical options are IPSec, WireGuard, and L2TP/IPSec.
ICCID, IMSI, and IMEI
ICCID identifies the physical SIM chip. IMSI identifies the subscriber on the mobile network. IMEI identifies the device (modem) holding the SIM. Three different identifiers, all three needed to manage an IoT fleet.