Secure Tunnels Between Docker Hosts

Two containers on the same docker host can talk to each other freely, but the moment they’re on hosts in different locations, that traffic crosses the open internet unprotected. docker-stunnel is a small stunnel wrapper for exactly that gap: run it with -s on the host with the service to protect, run it as a plain client on the other end pointed at that server, and the two docker hosts get an encrypted transport layer between them without touching the containers on either side.