CloudflareDNSUpdater

Updates DNS entries with a machines current IP address (internal or external).

A tool useful in environments with dynamically changing IP addresses, eg. NAT, DHCP, IPv6 SLAAC or other non-statically configured systems.

Currently this tool is limited to using the Cloudflare API and thus is limited to Cloudflare nameservers.

Features

• Updating IP once (eg. for cron jobs)
• Keeping track of IP changes via local netlink, ipify or periodic interface checks
• Applicable for NAT environments with ipify
• Only update record at Cloudflare when required, minimizes requests to Cloudflare
• Robust concept aiming to run as a service/background task

Requirements

Python version 3.7

pip modules: (can be installed with setup.py or via pip3 install -r requirements.txt)

• CloudFlare
• pyroute
• more: see requirements.txt

Installation

As simple as:

sudo python3 setup.py install

Usage overview

If you use setup.py the script updatecfdns will be installed in your PATH making it available on the command line.

Usage on CLI:

updatecfdns --config <configfile> <address type> <mode> <tracker> [<tracker arguments>]

Address type

This tool is capable of tracking IPv4 or IPv6 addresses.

• IPv4: --ipv4 or -4
• IPv6: --ipv6 or -6

Modes

Auto mode

The auto mode will keep track of IP changes and update a DNS entry accordingly.

You can specify --restart <seconds> to automatically restart the tracker to increase robustness. Per default this is done after one day.

Manual mode

The manual mode will trigger an update once (if required) and exit afterwards. Useful eg. for cron jobs.

Tracker

Tracker are the modules that keep track of an IP address change or define the way an IP address is determined.

	netlink	ipify	socket
NAT support	no	yes	no
External service contacted	no	yes	no
Update latency	instant	configurable in seconds	configurable in seconds
Requirements	netlink API (Linux), pyroute	Internet connection	-

Trackers can have custom arguments, for more details, append --help to the command line.

Config file

[api]
email = your.cloudflare.email@address.com
token = YoUrCL0udFlAR3APIt0KEn

[record]
zone = domain.com
name = subdomain.domain.com

Docker

This project ships with a Dockerfile providing a basic Alpine Linux based container. Its usage is analogue to the standard CLI:

1. Build: docker build . -t patgrosse/cfdnsupdater
2. Use: docker run --net=host -v <path/to/configfile.ini>:/config.ini patgrosse/cfdnsupdater --config /config.ini <arguments>

Example:

docker run --net=host -v /home/patrick/.secrets/dns_config.ini:/config.ini patgrosse/cfdnsupdater --config /config.ini -6 --auto netlink

Docker compose

See docker-compose.yml for an example.

Notes

• You have to create the DNS entry at Cloudflare yourself, it is not created automatically by this tool.