When purchasing SIM services you’ll often have the choice of a private or public IP. While it may seem that a public IP will have the best benefits, that isn’t always the case.
Based around sensors, meters and discrete devices, the traditional M2M world has always concerned itself with one way or simple two way communication. For example, a water meter may report flow rates once per hour to a server in the cloud, with the server responding back to acknowledge the information or send out new instructions. In a deployment like this, the device will be assigned a private IP, with the Network Address Translation (NAT) facilitating the Internet access.
Since the IP is private, the device can’t be accessed directly from the Internet. However, two-way communication is still possible when the device is the one initiating the communication. In this case the ISP will remember that the device tried to reach the Internet and the return traffic will be forwarded to the device.
There are multiple examples all around us of the way private IP services operate. For a good parallel take a look at your home broadband connection. All of your devices are assigned private IP’s, but they all work perfectly because as you browse or download files from the Internet, it’s your device initiating a connection to the outside world. Your router acts as a public IP, handling all the traffic and NAT.
Public IP’s expose devices to the outside world. Any system on the Internet can directly access a public IP, and it is up to the security on the device to control access. This is important to consider when choosing an IP type, as having a public IP can be a double edged sword.
On the one hand, a public IP may be necessary depending on the application. For example, an office connectivity solution with bespoke servers or VoIP phones may require a static public IP. However a public IP on the end user’s router will leave the router exposed to the rest of the internet and in turn vulnerable to attacks. Additionally, it’s important to consider that this will also generate extra usage since the service provider will simply route all traffic to the SIM card in the device.
For these reasons, it is important have a full understanding of what IP addressing a customer may need, and to always build connectivity for solutions based around these specific requirements.
Feel free to to get in touch with Pangea for help with any solutions you are building.