Occasionally you may see the Dropbox desktop client making HTTP connections to other locations. We do this to collect data on TLS connection failures.
Periodically, we send a “ping” to our servers via both HTTP and HTTPS. The Dropbox service compares and aggregates such pings and generates statistics that our engineers can use to identify whether there is a rise in rates of TLS connection troubles. This allows us to continuously improve our service quality and provide early warning of potential problems.
Data sent to Dropbox via this mechanism does not contain any personally identifiable information, client log information, file metadata or contents. Nevertheless, we encrypt the data with public-key cryptography to protect confidentiality and integrity.