Mastering Internet of Things

Limiting connectivity

One of the limitations of the HTTP protocol is that only the client can initiate communication over a connection. If both actors are reachable from each other, both can connect to each other and perform requests on each other over two different connections. But typically, web clients reside behind firewalls. These protect private Local Area Networks, or LANs, from incoming connections. While this is a good solution to protect private computers in cases where people navigate the web using web clients, it poses a problem for the Internet of Things.

In the traditional sense, the web server contains the interesting information (the pages), and clients consume them from their private network. The server resides publicly on ...