In some cases, it is necessary to disable Docker's IPtables rules to avoid overwriting any existing firewall rules. The following article describes a simple to follow procedure on how to disable disable Docker's IPtables rules on Systemd Linux systems.
Privileged access to your Systemd Linux is required.
# - requires given command to be executed with root privileges either directly as a root user or by use of sudo command
$ - given command to be executed as a regular non-privileged user
Create new Systemd Service
First, create a new directory:
# mkdir /etc/systemd/system/docker.service.d
Create a new service configuration file iptables-disabled.conf inside the previously created directory /etc/systemd/system/docker.service.d/ with a following content: