On 25 October 2016 at 09:37, Jean-Francois Mezei < jfmezei_nanog@vaxination.ca> wrote:
One way around this is for the pet feeder to initiate outbound connection to a central server, and have the pet onwer connect to that server to ask the server to send command to his pet feeder to feed the dog.
This is pretty common but, IMHO, the worst solution to this problem. It creates a dependence on a cloud service which is typically undocumented (what protocol do they use? where is the server located, China?); a centralised service is a security risk in it's own right (crack one server, own all the pet feeders); and it is liable to disappear when the operator goes out of business, rendering all the products sold useless. A strength of IP is that it is fundamentally a peer-to-peer protocol, please don't break that. NAT broke it but IPv6 can fix it again. There's nothing wrong with accepting incoming connections if the device is secure. If your problem is security, fix that. Don't throw the baby out with the bath water. Aled