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Fail2ban Docker image to ban hosts that cause multiple authentication errors.


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Build locally

git clone
cd docker-fail2ban

# Build image and output to docker (default)
docker buildx bake

# Build multi-platform image
docker buildx bake image-all


Registry Image
Docker Hub crazymax/fail2ban
GitHub Container Registry

Following platforms for this image are available:

$ docker run --rm mplatform/mquery crazymax/fail2ban:latest
Image: crazymax/fail2ban:latest
 * Manifest List: Yes
 * Supported platforms:
   - linux/amd64
   - linux/arm/v6
   - linux/arm/v7
   - linux/arm64
   - linux/386
   - linux/ppc64le
   - linux/s390x

Environment variables

  • TZ: The timezone assigned to the container (default UTC)
  • F2B_LOG_TARGET: Set the log target. This could be a file, SYSLOG, STDERR or STDOUT (default STDOUT)
  • F2B_LOG_LEVEL: Log level output (default INFO)
  • F2B_DB_PURGE_AGE: Age at which bans should be purged from the database (default 1d)
  • IPTABLES_MODE: Choose between iptables nft or legacy mode. (default auto)
  • SSMTP_HOST: SMTP server host
  • SSMTP_PORT: SMTP server port (default 25)
  • SSMTP_HOSTNAME: Full hostname (default $(hostname -f))
  • SSMTP_USER: SMTP username
  • SSMTP_TLS: Use TLS to talk to the SMTP server (default NO)
  • SSMTP_STARTTLS: Specifies whether ssmtp does a EHLO/STARTTLS before starting SSL negotiation (default NO)


SSMTP_PASSWORD_FILE can be used to fill in the value from a file, especially for Docker's secrets feature.


  • /data: Contains customs jails, actions and filters and Fail2ban persistent database


Docker Compose

Docker compose is the recommended way to run this image. Copy the content of folder examples/compose in /var/fail2ban/ on your host for example. Edit the Compose and env files with your preferences and run the following commands:

$ docker compose up -d
$ docker compose logs -f

Command line

You can also use the following minimal command :

$ docker run -d --name fail2ban --restart always \
  --network host \
  --cap-add NET_ADMIN \
  --cap-add NET_RAW \
  -v $(pwd)/data:/data \
  -v /var/log:/var/log:ro \


Recreate the container whenever I push an update:

$ docker compose pull
$ docker compose up -d



In Docker 17.06 and higher through docker/libnetwork#1675, you can add rules to a new table called DOCKER-USER, and these rules will be loaded before any rules Docker creates automatically. This is useful to make iptables rules created by Fail2Ban persistent.

If you have an older version of Docker, you may just change the chain definition for your jail to chain = FORWARD. This way, all Fail2Ban rules come before any Docker rules but these rules will now apply to ALL forwarded traffic.

More info :


If your Fail2Ban container is attached to DOCKER-USER chain instead of INPUT, the rules will be applied only to containers. This means that any packets coming into the INPUT chain will bypass these rules that now reside under the FORWARD chain.

This is why the sshd jail contains a chain = INPUT in its definition and traefik jail contains chain = DOCKER-USER.

Jails examples

Here are some examples using the DOCKER-USER chain:

And others using the INPUT chain:

Use fail2ban-client

Fail2ban commands can be used through the container. Here is an example if you want to ban an IP manually:

$ docker exec -t <CONTAINER> fail2ban-client set <JAIL> banip <IP>

Global jail configuration

You can provide customizations in /data/jail.d/*.local files.

For example to change the default bantime for all jails, send an e-mail with whois report and relevant log lines to the destemail:

bantime = 1h
destemail = root@localhost
sender = root@$(hostname -f)
action = %(action_mwl)s


If you want email to be sent after a ban, you have to configure SSMTP env vars

FYI, here is the order jail configuration would be loaded:

jail.d/*.conf (in alphabetical order)
jail.d/*.local (in alphabetical order)

A sample configuration file is available on the official repository.

Custom jails, actions and filters

Custom jails, actions and filters can be added respectively in /data/jail.d, /data/action.d and /data/filter.d. If you add an action/filter that already exists, it will be overriden.


Container has to be restarted to propagate changes


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Thanks again for your support, it is much appreciated! 🙏


MIT. See LICENSE for more details.