[](https://microbadger.com/images/linuxserver/duckdns "Get your own version badge on microbadger.com")
[Duckdns](https://duckdns.org/) is a free service which will point a DNS (sub domains of duckdns.org) to an IP of your choice. The service is completely free, and doesn't require reactivation or forum posts to maintain its existence.
Our images support multiple architectures such as `x86-64`, `arm64` and `armhf`. We utilise the docker manifest for multi-platform awareness. More information is available from docker [here](https://github.com/docker/distribution/blob/master/docs/spec/manifest-v2-2.md#manifest-list) and our announcement [here](https://blog.linuxserver.io/2019/02/21/the-lsio-pipeline-project/).
Docker images 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.
## 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__PASSWORD=/run/secrets/mysecretpassword
```
Will set the environment variable `PASSWORD` based on the contents of the `/run/secrets/mysecretpassword` 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](https://en.wikipedia.org/wiki/Umask) before asking for support.
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`.
[](https://mods.linuxserver.io/?mod=duckdns "view available mods for this container.")
We publish various [Docker Mods](https://github.com/linuxserver/docker-mods) to enable additional functionality within the containers. The list of Mods available for this image (if any) can be accessed via the dynamic badge above.
