Got some IP data-loggers (that measure temp., humidity, light-level) sitting inside bunch of warehouses / stores with each warehouse / store being a different customer from my standpoint. These data-loggers provide information over clear-channel HTTP (Basic-Authentication). Also, my server sends out commands (again over HTTP) to data-logger, to reboot, do firmware upgrade etc. The way I have it rigged up today is those are assigned IP-address in the private-192.168.X.X range, each with a unique TCP port#, and the ADSL-Router does port-mapping to make those visible to my server which polls those data-loggers (at each site) every 5 minutes, to download base64 encoded data. The data-loggers cannot be software upgraded (I've no control over them), yet, I would somehow secure the flow of information from the ADSL-router to my server. Today the number of such customers is small and manageable, but I would like to scale this out, thus looking for a solution that scales well, provides me with necessary security, and is cost-effective.
My expectations of 'security' here are:- - No eavsdropping / snooping - No man-in-the-middle - No tampering - No spoofing It is safe to assume that my main interest is in ensuring that the connectivity between my server and the ADSL-router is secure. Inside the warehouse, I am not worried as much.
On the ADSL router, I have the firewall up, with holes poked (obviously) for the specific ports corresponding to the data-loggers and the mapping created. Could VPN be an answer ? What are some of the alternatives, gotchas, pit-falls etc.
Appreciate explanation, pointers, suggestions etc.