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linuxserver/endlessh

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Endlessh is an SSH tarpit that very slowly sends an endless, random SSH banner. It keeps SSH clients locked up for hours or even days at a time. The purpose is to put your real SSH server on another port and then let the script kiddies get stuck in this tarpit instead of bothering a real server.

endlessh

Supported Architectures

We utilise the docker manifest for multi-platform awareness. More information is available from docker here and our announcement here.

Simply pulling lscr.io/linuxserver/endlessh:latest should retrieve the correct image for your arch, but you can also pull specific arch images via tags.

The architectures supported by this image are:

Architecture Available Tag
x86-64 amd64-<version tag>
arm64 arm64v8-<version tag>
armhf

Application Setup

The app listens on the port mapped for ssh connections. To log to file, set the environment variable LOGFILE to true and map a volume for /config. The logs will be under /config/logs/endlessh.

Usage

To help you get started creating a container from this image you can either use docker-compose or the docker cli.

---
version: "2.1"
services:
  endlessh:
    image: lscr.io/linuxserver/endlessh:latest
    container_name: endlessh
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Etc/UTC
      - MSDELAY=10000 #optional
      - MAXLINES=32 #optional
      - MAXCLIENTS=4096 #optional
      - LOGFILE=false #optional
      - BINDFAMILY= #optional
    volumes:
      - /path/to/appdata:/config #optional
    ports:
      - 22:2222
    restart: unless-stopped

docker cli (click here for more info)

docker run -d \
  --name=endlessh \
  -e PUID=1000 \
  -e PGID=1000 \
  -e TZ=Etc/UTC \
  -e MSDELAY=10000 `#optional` \
  -e MAXLINES=32 `#optional` \
  -e MAXCLIENTS=4096 `#optional` \
  -e LOGFILE=false `#optional` \
  -e BINDFAMILY= `#optional` \
  -p 22:2222 \
  -v /path/to/appdata:/config `#optional` \
  --restart unless-stopped \
  lscr.io/linuxserver/endlessh:latest

Parameters

Containers are configured using parameters passed at runtime (such as those above). These parameters are separated by a colon and indicate <external>:<internal> respectively. For example, -p 8080:80 would expose port 80 from inside the container to be accessible from the host's IP on port 8080 outside the container.

Ports (-p)

Parameter Function
2222 ssh port

Environment Variables (-e)

Env Function
PUID=1000 for UserID - see below for explanation
PGID=1000 for GroupID - see below for explanation
TZ=Etc/UTC specify a timezone to use, see this list.
MSDELAY=10000 The endless banner is sent one line at a time. This is the delay in milliseconds between individual lines.
MAXLINES=32 The length of each line is randomized. This controls the maximum length of each line. Shorter lines may keep clients on for longer if they give up after a certain number of bytes.
MAXCLIENTS=4096 Maximum number of connections to accept at a time. Connections beyond this are not immediately rejected, but will wait in the queue.
LOGFILE=false By default, the app logs to container log. If this is set to true, the log will be output to file under /config/logs/endlessh (/config needs to be mapped).
BINDFAMILY= By default, the app binds to IPv4 and IPv6 addresses. Set it to 4 or 6 to bind to IPv4 only or IPv6 only, respectively. Leave blank to bind to both.

Volume Mappings (-v)

Volume Function
/config Required if LOGFILE is set to true.

Miscellaneous Options

Parameter Function

Environment variables from files (Docker secrets)

You can set any environment variable from a file by using a special prepend FILE__.

As an example:

-e FILE__MYVAR=/run/secrets/mysecretvariable

Will set the environment variable MYVAR based on the contents of the /run/secrets/mysecretvariable file.

Umask for running applications

For all of our images we provide the ability to override the default umask settings for services started within the containers using the optional -e UMASK=022 setting. Keep in mind umask is not chmod it subtracts from permissions based on it's value it does not add. Please read up here before asking for support.

User / Group Identifiers

When using volumes (-v flags), permissions issues can arise between the host OS and the container, we avoid this issue by allowing you to specify the user PUID and group PGID.

Ensure any volume directories on the host are owned by the same user you specify and any permissions issues will vanish like magic.

In this instance PUID=1000 and PGID=1000, to find yours use id your_user as below:

id your_user

Example output:

uid=1000(your_user) gid=1000(your_user) groups=1000(your_user)

Docker Mods

Docker Mods Docker Universal Mods

We publish various Docker Mods to enable additional functionality within the containers. The list of Mods available for this image (if any) as well as universal mods that can be applied to any one of our images can be accessed via the dynamic badges above.

Support Info

  • Shell access whilst the container is running:

    docker exec -it endlessh /bin/bash
    
  • To monitor the logs of the container in realtime:

    docker logs -f endlessh
    
  • Container version number:

    docker inspect -f '{{ index .Config.Labels "build_version" }}' endlessh
    
  • Image version number:

    docker inspect -f '{{ index .Config.Labels "build_version" }}' lscr.io/linuxserver/endlessh:latest
    

Updating Info

Most of our images are static, versioned, and require an image update and container recreation to update the app inside. With some exceptions (ie. nextcloud, plex), we do not recommend or support updating apps inside the container. Please consult the Application Setup section above to see if it is recommended for the image.

Below are the instructions for updating containers:

Via Docker Compose

  • Update images:

    • All images:

      docker-compose pull
      
    • Single image:

      docker-compose pull endlessh
      
  • Update containers:

    • All containers:

      docker-compose up -d
      
    • Single container:

      docker-compose up -d endlessh
      
  • You can also remove the old dangling images:

    docker image prune
    

Via Docker Run

  • Update the image:

    docker pull lscr.io/linuxserver/endlessh:latest
    
  • Stop the running container:

    docker stop endlessh
    
  • Delete the container:

    docker rm endlessh
    
  • Recreate a new container with the same docker run parameters as instructed above (if mapped correctly to a host folder, your /config folder and settings will be preserved)

  • You can also remove the old dangling images:

    docker image prune
    

Via Watchtower auto-updater (only use if you don't remember the original parameters)

  • Pull the latest image at its tag and replace it with the same env variables in one run:

    docker run --rm \
      -v /var/run/docker.sock:/var/run/docker.sock \
      containrrr/watchtower \
      --run-once endlessh
    
  • You can also remove the old dangling images: docker image prune

Warning

We do not endorse the use of Watchtower as a solution to automated updates of existing Docker containers. In fact we generally discourage automated updates. However, this is a useful tool for one-time manual updates of containers where you have forgotten the original parameters. In the long term, we highly recommend using Docker Compose.

Image Update Notifications - Diun (Docker Image Update Notifier)

Tip

We recommend Diun for update notifications. Other tools that automatically update containers unattended are not recommended or supported.

Building locally

If you want to make local modifications to these images for development purposes or just to customize the logic:

git clone https://github.com/linuxserver/docker-endlessh.git
cd docker-endlessh
docker build \
  --no-cache \
  --pull \
  -t lscr.io/linuxserver/endlessh:latest .

The ARM variants can be built on x86_64 hardware using multiarch/qemu-user-static

docker run --rm --privileged multiarch/qemu-user-static:register --reset

Once registered you can define the dockerfile to use with -f Dockerfile.aarch64.

Versions

  • 12.06.23: - Rebase to Alpine 3.18, deprecate armhf.
  • 05.03.23: - Rebase to Alpine 3.17.
  • 23.09.22: - Migrate to s6v3.
  • 20.07.22: - Rebase to Alpine 3.16.
  • 16.04.22: - Rebase to Alpine 3.15.
  • 07.10.21: - Fix typo on MAXLINES var.
  • 08.06.21: - Add BINDFAMILY option.
  • 16.04.21: - Initial Release.

Last update: November 17, 2023
Created: February 5, 2019