Fail2ban Docker image to ban hosts that cause multiple authentication errors.
Note
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git clone https://github.com/crazy-max/docker-fail2ban.git
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 | ghcr.io/crazy-max/fail2ban |
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
TZ
: The timezone assigned to the container (defaultUTC
)F2B_LOG_TARGET
: Set the log target. This could be a file, SYSLOG, STDERR or STDOUT (defaultSTDOUT
)F2B_LOG_LEVEL
: Log level output (defaultINFO
)F2B_DB_PURGE_AGE
: Age at which bans should be purged from the database (default1d
)SSMTP_HOST
: SMTP server hostSSMTP_PORT
: SMTP server port (default25
)SSMTP_HOSTNAME
: Full hostname (default$(hostname -f)
)SSMTP_USER
: SMTP usernameSSMTP_PASSWORD
: SMTP passwordSSMTP_TLS
: Use TLS to talk to the SMTP server (defaultNO
)SSMTP_STARTTLS
: Specifies whether ssmtp does a EHLO/STARTTLS before starting SSL negotiation (defaultNO
)
Note
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 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
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 \
crazymax/fail2ban:latest
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 : https://docs.docker.com/network/iptables/
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
.
Here are some examples using the DOCKER-USER
chain:
And others using the INPUT
chain:
As you may know, nftables is available as a modern replacement for the kernel's iptables subsystem on Linux.
This image still uses iptables
to preserve backwards compatibility but an issue is opened
about its implementation.
If your system's iptables
tooling uses the nftables backend, this will throw
the error stderr: 'iptables: No chain/target/match by that name.'
. You need
to switch the iptables
tooling to 'legacy' mode to avoid these problems. This
is the case on at least Debian 10 (Buster), Ubuntu 19.04, Fedora 29 and newer
releases of these distributions by default. RHEL 8 does not support switching
to legacy mode, and is therefore currently incompatible with this image.
On Ubuntu or Debian:
$ update-alternatives --set iptables /usr/sbin/iptables-legacy
$ update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
$ update-alternatives --set arptables /usr/sbin/arptables-legacy
$ update-alternatives --set ebtables /usr/sbin/ebtables-legacy
On Fedora:
$ update-alternatives --set iptables /usr/sbin/iptables-legacy
Then reboot to apply changes.
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>
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:
[DEFAULT]
bantime = 1h
destemail = root@localhost
sender = root@$(hostname -f)
action = %(action_mwl)s
Warning
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.conf
jail.d/*.conf (in alphabetical order)
jail.local
jail.d/*.local (in alphabetical order)
A sample configuration file is available on the official repository.
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.
Warning
Container has to be restarted to propagate changes
Want to contribute? Awesome! The most basic way to show your support is to star the project, or to raise issues. You can also support this project by becoming a sponsor on GitHub or by making a Paypal donation to ensure this journey continues indefinitely!
Thanks again for your support, it is much appreciated! ๐
MIT. See LICENSE
for more details.