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https://github.com/homeall/dhcphelper

DHCP relay for DHCP Server in the docker container.
https://github.com/homeall/dhcphelper

broadcast dhcp dhcp-relay dhcp-server dhcphelper dhcpoffer dhcpoffer-messages docker pihole

Last synced: 3 days ago
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DHCP relay for DHCP Server in the docker container.

Host: GitHub
URL: https://github.com/homeall/dhcphelper
Owner: homeall
License: epl-2.0
Created: 2020-12-24T23:05:19.000Z (almost 4 years ago)
Default Branch: main
Last Pushed: 2024-09-23T19:53:37.000Z (10 days ago)
Last Synced: 2024-09-25T21:32:41.364Z (8 days ago)
Topics: broadcast, dhcp, dhcp-relay, dhcp-server, dhcphelper, dhcpoffer, dhcpoffer-messages, docker, pihole
Language: Dockerfile
Homepage:
Size: 234 KB
Stars: 25
Watchers: 1
Forks: 2
Open Issues: 0
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Security: SECURITY.md

Awesome Lists containing this project

README

[![dhcphelper](https://github.com/homeall/dhcphelper/workflows/CI/badge.svg)](https://github.com/homeall/dhcphelper/actions) [![pull](https://img.shields.io/docker/pulls/homeall/dhcphelper)](https://img.shields.io/docker/pulls/homeall/dhcphelper) [![pull](https://img.shields.io/docker/image-size/homeall/dhcphelper)](https://img.shields.io/docker/image-size/homeall/dhcphelper) [![contributions welcome](https://img.shields.io/badge/contributions-welcome-brightgreen.svg?style=flat)](https://ionut.vip)

# DHCP Relay in docker

Table of Contents

About The Project

Getting Started
- Prerequisites

Usage
- Potentials issues
- Testing
- PiHole and DHCP Relay

License

Contact

Acknowledgements

## About The Project

This is a small docker image with a [DHCP Helper](http://www.thekelleys.org.uk/dhcp-helper/) useful in case when you have a DHCP server in the docker environment and you need a relay for broadcast.

The DHCP server in the container does get only *unicast the DHCPOFFER messages* when it will have to get **broadcast DHCPOFFER messages** on the [network](https://stackoverflow.com/questions/38816077/run-dnsmasq-as-dhcp-server-from-inside-a-docker-container).

It will **not** work the DHCP server in docker even in **networking host mode** unless you are using any DHCP relay.

:man_student: If you need to know more about how it works **DHCP protocol**, I highly recommend this [link](https://superuser.com/questions/811501/understanding-dhcp-discovery-specific-subnet).

## Getting Started

:beginner: It will work on any Linux box amd64 or [Raspberry Pi](https://www.raspberrypi.org) with arm64 or arm32.

### Prerequisites

[![Made with Docker !](https://img.shields.io/badge/Made%20with-Docker-blue)](https://github.com/homeall/dhcphelper/blob/main/Dockerfile)

You will need to have:

* :whale: [Docker](https://docs.docker.com/engine/install/)
* :whale2: [docker-compose](https://docs.docker.com/compose/)
>This step is optional

## Usage

You only need to pass as variable the IP address of DHCP server: `"-e IP=X.X.X.X"`

You can run as:

`docker run --privileged -d --name dhcp --net host -e "IP=172.31.0.100" homeall/dhcphelper:latest`

![](./assets/dhcphelper.gif)

### Potentials issues

:warning: Please make sure your host has port **67 on UDP** *open* on **iptables/firewall** of your OS and it is running on network host mode **ONLY**.

:bangbang: You can run the following command to see that is working:

```
$ nc -uzvw3 127.0.0.1 67
Connection to 127.0.0.1 port 67 [udp/bootps] succeeded!
```

:hearts: On the status column of the docker, you will notice the `healthy` word. This is telling you that docker is running [healtcheck](https://scoutapm.com/blog/how-to-use-docker-healthcheck) itself in order to make sure it is working properly. Please test yourself using the following command:

```
$ docker inspect --format "{{json .State.Health }}" dhcp | jq
{
"Status": "healthy",
"FailingStreak": 0,
"Log": [
{
"Start": "2021-01-04T10:28:11.8070681Z",
"End": "2021-01-04T10:28:14.8695872Z",
"ExitCode": 0,
"Output": "127.0.0.1 (127.0.0.1:67) open\n"
}
]
}
```
:arrow_up: [Go on TOP](#about-the-project) :point_up:

### Testing

:arrow_right: You can run a command from Linux/Mac:

`$ sudo nmap --script broadcast-dhcp-discover -e $Your_Interface`

:arrow_down: Output result:

### [PiHole](https://github.com/pi-hole/pi-hole) and DHCP Relay

:moneybag: It will work amazing both together **dhcphelper** and :copyright: [PiHole](https://github.com/pi-hole/pi-hole) :yin_yang:

:sparkle: A simple [docker-compose.yml](https://docs.docker.com/compose/):

```
version: "3.3"

services:
pihole:
container_name: pihole
image: pihole/pihole:latest
hostname: pihole
ports:
- "53:53/tcp"
- "53:53/udp"
- "80:80/tcp"
environment:
TZ: 'Europe/London'
WEBPASSWORD: 'admin'
DNS1: '127.0.0.53'
DNS2: 'no'
volumes:
- './etc-pihole/:/etc/pihole/'
depends_on:
- dhcphelper
cap_add:
- NET_ADMIN
restart: unless-stopped
networks:
backend:
ipv4_address: '172.31.0.100'
proxy-tier: {}

dhcphelper:
restart: unless-stopped
container_name: dhcphelper
network_mode: "host"
image: homeall/dhcphelper:latest
environment:
IP: '172.31.0.100'
TZ: 'Europe/London'
cap_add:
- NET_ADMIN
```
:arrow_up: [Go on TOP](#about-the-project) :point_up:

## License

:newspaper_roll: Distributed under the MIT license. See [LICENSE](https://raw.githubusercontent.com/homeall/dhcphelper/main/LICENSE) for more information.

## Contact

:red_circle: Please free to open a ticket on Github.

## Acknowledgements

* :tada: [@DerFetzer](https://discourse.pi-hole.net/t/dhcp-with-docker-compose-and-bridge-networking/17038) :trophy:
* :tada: [@Simon Kelley](http://www.thekelleys.org.uk/dhcp-helper/) who is the **author** of *dnsmasq* and *dhcp-helper*. :1st_place_medal:

:arrow_up: [Go on TOP](#about-the-project) :point_up: