Docker image for ISC DHCP server

This Docker image is suitable for running a DHCP server for your docker host network. It uses ISC DHCP server which is bundled with the latest Ubuntu LTS distribution.

How to build

1. Install Docker with the instructions on https://www.docker.com.
2. Run ./build to create the local docker image networkboot/dhcpd.

How to use

The most common use-case is to provide DHCP service to the host network of the machine running Docker. For that you need to create a configuration for the DHCP server, start the container with the --net host docker run option and specify the network interface you want to provide DHCP service on.

1. Create data folder.
2. Create data/dhcpd.conf with a subnet clause for the specified network interface. If you need assistance, you can run docker run -it --rm networkboot/dhcpd man dhcpd.conf for a description of the configuration file syntax.
3. Run docker run -it --rm --init --net host -v "$(pwd)/data":/data networkboot/dhcpd eth0. dhcpd will automatically start and display its logs on the console. You can press Ctrl-C to terminate the server.

A simple run script is also included which makes it quick to iterate on a configuration until you're satisfied.

DHCPv6

To use a DHCPv6-Server you have to pass DHCPD_PROTOCOL=6 as enviroment variable

docker run -it --rm --init -e DHCPD_PROTOCOL=6 --net host -v "$(pwd)/data":/data networkboot/dhcpd eth0

Notes

The entrypoint script in the docker image takes care of running the DHCP server as the same user that owns the data folder. This ensures that the permissions on the files inside the data folder is kept consistent. If the data folder is owned by root, dhcpd is run as the normal dhcpd user.

If you forget to run the docker container with the --net host option a warning will be emitted informing you that you've probably forgotten it.

If a /data volume is not provided with a dhcpd.conf inside it, the container will exit early with an error message.

An additional Dockerfile has been added that allows building an image with the tag :ldap which contains the isc-dhcp-server-ldap package in addition to the normal DHCP server package. Other than that it behaves in exactly the same way as the :latest tag. Utility build and run scripts have also been added to work with this variant.

Acknowledgements

This image uses the following software components:

• Ubuntu Linux distribution from https://www.ubuntu.com.
• ISC DHCP server from https://www.isc.org/downloads/dhcp/.
• Dumb-init from https://github.com/Yelp/dumb-init.

Copyright & License

This project is copyright 2022 Robin Smidsrød robin@smidsrod.no.

It is licensed under the Apache 2.0 license.

See the file LICENSE for full legal details.