UFW firewall is not working on Ubuntu in DigitalOcean

Question

In my DigitalOcean (DO) droplet I installed this image: Ubuntu Docker 17.12.0~ce on 16.04 (which is available on ** DO website > droplet> destroy> rebuild dropl

Answer 1

Docker and UFW don't work together too well as they both modify iptables but there's a way to fix this. You'll need to configure Docker to not use iptables. Add

DOCKER_OPTS="--iptables=false"

to /etc/default/docker and restart your host (or restart the Docker daemon and UFW).

These two links have a lot more information about the issue:

https://blog.viktorpetersson.com/2014/11/03/the-dangers-of-ufw-docker.html
https://www.techrepublic.com/article/how-to-fix-the-docker-and-ufw-security-flaw/