The same thing happened to me a few years ago. I used DigitalOcean's Docker image and it had some message about UFW in motd, so I assumed it works with Docker.

The same thing happened to me a few years ago. I used DigitalOcean's Docker image and it had some message about UFW in motd, so I assumed it works with Docker. So I created a container with passwordless mongodb and it got wiped in a few hours. And DO still have this in motd for newly created droplets: Welcome to DigitalOcean's 1-Click Docker Droplet. To keep this Droplet secure, the UFW firewall is enabled. All ports are BLOCKED except 22 (SSH), 2375 (Docker) and 2376 (Docker). Full motd: https://pastebin.com/cdaecHU8 https://pastebin.com/cdaecHU8 Though it links to https://do.co/3j6j3po https://do.co/3j6j3po and it mentions ufw problem: > Note: The default firewall for the Docker One-Click is UFW, which is a front end to iptables. However, Docker modifies iptables directly to set up communication to and from containers. This means that UFW won’t give you a full picture of the firewall settings. You can override this behavior in Docker by adding --iptables=false to the Docker daemon.