DreamHost Dynamic DNS Record Update

dhdynupdate is a Python 3 utility for Linux. Other operating systems may work, but have not been tested.

The purpose of dhdynupdate is similar to a number of dynamic DNS updaters on the internet: to update DNS records with IP addresses for your local machine for a domain hosted by DreamHost, using the DreamHost API.

When started using the systemd service file, dhdynupdate as an unprivileged process. dhdynudpate can also execute as your user process.

Features

• dhdynupdate supports updating both A and AAAA (IPv4 and IPv6) addresses.
• DNS records are updated on an as-needed basis to avoid sending unnecessary DreamHost API calls
• dhdynupdate verifies & updates the DNS records for the configured hostname upon dæmon instantiation
  • From there, dhdynupdate check your local IPv4 and/or IPv6 addresses.
  • If a IPv4/IPv6 address changes, dhdynupdate will update the corresponding entry in your DreamHost DNS Zone.

Dependencies

dhdynupdate uses the following external modules:

• daemon
  • Available in Debian/Ubuntu as python3-daemon
• netifaces
  • Available in Debian/Ubuntu as python3-netifaces
• requests
  • Available in Debian/Ubuntu as python3-requests

Installation

No binary packages exist yet, but, I've tested the following configuration on a Debian Unstable/Sid system.

There is not an "easy" installation at this time; you will be required to copy files into their proper destinations, and create a user for the dæmon to execute as.

• Install dependencies:
  • On Debian or Ubuntu, you should be able to: apt-get install python3-daemon python3-netifaces python3-requests
• Create a dhdynupdate user/group for the dhdynupdate dæmon to execute as
• Copy (or clone) the git repository to /usr/local/dhdyupdate
• Copy dhdynupdate.conf to /etc/
• Create a directory for the logfile: mkdir -p /var/log/dhdynupdate chown dhdynupdate:dhdynupdate /var/log/dhdynupdate
• Install/activate the systemd service file:
  • Copy dhdynupdate.service to /lib/systemd/system/
  • systemctl daemon-reload
  • systemctl enable dhdynupdate.service

Configuration

Configuration goes in dhdynupdate.conf, and is in the Python 'config' file format.

TL;DR config:

• Modify the following entires in /etc/dhdynudpate.conf:

  AF_INET = <interface with the IPv4 address you want to add to DreamHost DNS>
AF_INET6 = <interface with the IPv6 address you want to add to DreamHost DNS>

• Under [your.domain.com], modify:

  api_key = <your DreamHost API key> local_hostname = <the hostname you wish to add to DreamHost DNS>

Config File Sections

###Global This section has global configuration options:

• Network interfaces to update the DNS records for
• The DreamHost Web API URL, and the logfile location.

###DreamHost API Test Account

• Uses The DreamHost test API key
• Only allows read-only operations
• It's a useful example to show the file format as well as a harmless test

###your.domain.name

• Insert your.domain.name for the name of your domain name.

• Also put in your DreamHost API key.

    [Global]
    # The DreamHost API URL; doubtful it'll change
    api_url = https://api.dreamhost.com/
    # External IPv4 and IPv6 interface to use
    # Separated as the subnet provided by my ISP is on a different interface
    # than the routing IP on my external interface.
    # IPv4 is the AF_INET address family
    AF_INET = eth1
    # IPv6 is the AF_INET6 family
    AF_INET6 = eth0
    # Log file
    log_file = /var/log/dhdynupdate.log
    # The update interval (in seconds)
    # for reference, 1h = 3600 s
    update_interval = 3600
    # PID file location
    pidfile = /run/dhdynupdate/dhdynupdate.pid
    
    [DreamHost API Test Account]
    api_key = 6SHU5P2HLDAYECUM
    local_hostname = ssh.thebesthostever.com
    
    [your.domain.name]
    api_key=6SHU5P2HLDAYECUM
    local_hostname = a6.groo.com
  

Generating a DreamHost API Key

If you don't already have an appropriate API key:

• Generate a new API key:
  • Make sure that dns-* is checked
  • Make sure everything else is unchecked

Command-line usage

usage: dhdynupdate.py [-h] [-d] [--debug lvl] [-c config]

optional arguments:
  -h, --help            show this help message and exit
  -d, --daemon          Execute dhdynupdate.py as a dæmon
  --debug lvl           Log Level, one of CRITICAL, ERROR, WARNING, INFO,
                        DEBUG
  -c config, --config config
                        Configuration name

If executed in daemon mode, dhdynupdate will dæmonize into a background process, suitable for management using an init script or via systemd.

A config name is the name of the dhdynupdate.conf section you wish to use. Multiple hostnames and API keys can be configured, enabling you to configure multiple DNS domains or hostnames, and select which one to update at runtime.

For example, ./dhdynupdate.py -c your.domain.com will load the [your.domain.name] section in the dhdynupdate.conf.

TODO:

• Proper Python packaging
• Maybe an RPM or Debian package
• OS X support

FreeBSD License

Copyright (c) 2016, Troy Telford All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those of the authors and should not be interpreted as representing official policies, either expressed or implied.