Flush IP tables and restart docker

flush-iptables.sh

#!/bin/bash

# Script is needed because my default firewall rules are messed up and after
# every restart, docker containers can't make connections to the host, notably
# preventing debuggers like xdebug from attaching.

# If networking fails in your containers but works in others, rm and re-create the
# docker network that container is bound to.

set -euo pipefail

# Unless docker is stopped with no containers running, docker will leave zombie
# proxy processes that hold the ports open preventing the start of new containers.
# If this happens I have to kill them manually: https://stackoverflow.com/a/61239636/3779

if [ ! $(docker ps | wc -l) == "1" ]; then
  echo "Some docker containers are running."
  exit 0
fi


sudo service docker stop

sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT
sudo iptables -t nat -F
sudo iptables -t mangle -F
sudo iptables -F
sudo iptables -X

sudo service docker start

Hi Steve,

Many thanks for this very useful script! Indeed this allowed my local docker install to run certain applications that depend on a properly built firewall.

I had to add a # right before the first line so that it becomes #!/bin/bash. Other than that, everything seemed fine. Kudos! 🎉

Best,
Justine Leon

Saved me a bunch of hassle, many thanks!

🙌