Table of Contents

\n About The Project\n
\n Getting Started\n
- Prerequisites
\n
\n Usage\n
- Potentials issues
\n
- Testing
\n
- PiHole and DHCP Relay
\n
License
Contact
Acknowledgements

\n\n\n## About The Project \n\nYou can check the repo on [GitHub](https://github.com/homeall/dhcphelper).\n\nThis 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.\n\nThe 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).\n\nIt will **not** work the DHCP server in docker even in **networking host mode** unless you are using any DHCP relay.\n\nIf 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). \n\n\n## Getting Started\n\nIt will work on any Linux box amd64 or [Raspberry Pi](https://www.raspberrypi.org) with arm64 or arm32. \n\n### Prerequisites\n\nYou will need to have:\n\n* [Docker](https://docs.docker.com/engine/install/)\n* [docker-compose](https://docs.docker.com/compose/) `This step is optional.`\n\n\n## Usage\n\nYou only need to pass as variable the IP address of DHCP server: `\"-e IP=X.X.X.X\"`\n\nYou can run as:\n\n```docker run --privileged -d --name dhcp --net host -e \"IP=172.31.0.100\" homeall/dhcphelper:latest```\n\n![](https://github.com/homeall/dhcphelper/raw/main/assets/dhcphelper.gif)\n\n### Potentials issues\n\nPlease 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**.\n\nYou can run the following command to see that is working::\n\n```\n$ nc -uzvw3 127.0.0.1 67\nConnection to 127.0.0.1 port 67 [udp/bootps] succeeded!\n```\nOn 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:\n\n```\n$ docker inspect --format \"{{json .State.Health }}\" dhcp | jq\n{\n \"Status\": \"healthy\",\n \"FailingStreak\": 0,\n \"Log\": [\n {\n \"Start\": \"2021-01-04T10:28:11.8070681Z\",\n \"End\": \"2021-01-04T10:28:14.8695872Z\",\n \"ExitCode\": 0,\n \"Output\": \"127.0.0.1 (127.0.0.1:67) open\\n\"\n }\n ]\n}\n```\n\n### Testing\n\nYou can run a command from Linux/Mac:\n\n`$ sudo nmap --script broadcast-dhcp-discover -e $Your_Interface`\n\nOutput result:\n\n```\nStarting Nmap 7.91 ( https://nmap.org ) at 2021-01-01 19:40 GMT\nPre-scan script results:\n| broadcast-dhcp-discover:\n| Response 1 of 1:\n| Interface: en0\n| IP Offered: 192.168.1.30\n| DHCP Message Type: DHCPOFFER\n| Server Identifier: 172.31.0.100\n| IP Address Lease Time: 2m00s\n| Renewal Time Value: 1m00s\n| Rebinding Time Value: 1m45s\n| Subnet Mask: 255.255.255.0\n| Broadcast Address: 192.168.1.255\n| Domain Name Server: 172.31.0.100\n| Domain Name: lan\n| Router: 192.168.1.1\nNmap done: 0 IP addresses (0 hosts up) scanned in 10.26 seconds\n```\n\n### [PiHole](https://hub.docker.com/r/pihole/pihole) and DHCP Relay\n\nIt will work amazing both together **dhcphelper** and [PiHole](https://hub.docker.com/r/pihole/pihole) \n\nA simple [docker-compose.yml](https://docs.docker.com/compose/):\n\n```\nversion: \"3.3\"\n\nservices:\n pihole:\n container_name: pihole\n image: pihole/pihole:latest\n hostname: pihole\n ports:\n - \"53:53/tcp\"\n - \"53:53/udp\"\n - \"80:80/tcp\"\n environment:\n TZ: 'Europe/London'\n WEBPASSWORD: 'admin'\n DNS1: '127.0.0.53'\n DNS2: 'no'\n volumes:\n - './etc-pihole/:/etc/pihole/'\n depends_on:\n - dhcphelper\n cap_add:\n - NET_ADMIN\n restart: unless-stopped\n networks:\n backend:\n ipv4_address: '172.31.0.100'\n proxy-tier: {}\n\n dhcphelper:\n restart: unless-stopped\n container_name: dhcphelper\n network_mode: \"host\"\n image: homeall/dhcphelper:latest\n environment:\n TZ: 'Europe/London'\n IP: '172.31.0.100'\n cap_add:\n - NET_ADMIN\n```\n\n## License\n\nDistributed under the MIT license. See [LICENSE](https://raw.githubusercontent.com/homeall/dhcphelper/main/LICENSE) for more information.\n\n\n## Contact\n\nPlease free to open a ticket on Github.\n\n\n## Acknowledgements\n\n * [@DerFetzer](https://discourse.pi-hole.net/t/dhcp-with-docker-compose-and-bridge-networking/17038)\n * [@Simon Kelley](http://www.thekelleys.org.uk/dhcp-helper/) who is the **author** of *dnsmasq* and *dhcp-helper*.","has_starred","hub_user","immutable_tags_settings",{"_211":11,"_212":213},"enabled","rules",[214],".*","is_automated","permissions",{"_218":21,"_219":11,"_220":11},"read","write","admin","user","storage_size",1126511630,"isOrg","reponame","tag","sha256:2faaf05b2dd967509755343d590632ec6ffd3b917d9e3f5e96337790a9624c52","canDeleteTags","isHubSbxKitsEnabled","currentTab","tagAttestations","displaySecurityMetadata","showSbxLogoOverride","routes/_layout.layers.$namespace.$reponame.$tag.(images).($imageUrlDigest)._index",{"_27":28,"_165":-7,"_163":-7,"_164":-7,"_29":236,"_35":227,"_239":-7,"_240":11},{"_31":32,"_33":34,"_35":36,"_37":38,"_39":40,"_41":237,"_58":59,"_60":34,"_61":62,"_63":64,"_65":66,"_67":68,"_69":48,"_70":59,"_71":56,"_72":21},[238],{"_44":45,"_35":36,"_46":45,"_47":48,"_49":50,"_51":45,"_52":45,"_53":-5,"_54":38,"_55":56,"_57":-5},"imageWithLayers","hasPermissionToViewRepoSettings","actionData","errors"]

homeall/dhcphelper:sha256-2fef746b367354e1faf7c257a3496153b3aa3506ba02404e7019811b33322dce.sig