ddupdate 0.5.0

Update dns data for dynamic ip addresses

General

ddupdate is a tool for automatically updating dns data for a system using for example DHCP. It makes it possible to access the system with a fixed dns name such as myhost.somewhere.net even if the IP address is changed. It is a linux-centric, user-friendly, flexible and maintainable alternative to the ubiquitous ddclient.

Status

Beta. The plugin API will be kept stable up to 1.0.0, and there should be no incompatible CLI changes.

At the time of writing 14 free services are supported.

The address plugins supports ipv4 or ipv6 addresses using::

• The external address as seen from the net.

• The address on a given interface, or the default one.

• A hardcoded (configured) address.

• The address returned by a command.

Still, this is beta and there is most likely bugs out there.

Dependencies

• python3 (tested on 3.6 and 3.4)

• python3-straight-plugin (a. k. a. python3-straight.plugin)

• python3-setuptools

• The /usr/sbin/ip command is used in some plugins.

• The configuration script requires sudo.

Installation

ddupdate can be run as a regular user straight off the cloned git directory. To make it possible to run from anywhere make a symlink:

$ ln -s $PWD/ddupdate $HOME/bin/ddupdate

It is also possible to install as a pypi package using:

$ sudo pip install ddupdate --prefix=/usr/local

User installations are not supported, but installing in a virtual env is - see Packaging in CONTRIBUTE.md.

Fedora and Mageia users can install native packages from https://copr.fedorainfracloud.org/coprs/leamas/ddupdate/.

Ubuntu users can use the PPA at https://launchpad.net/~leamas-alec/+archive/ubuntu/ddupdate

CONTRIBUTE.md describes how to create Debian packages. Here is also more info on using the pypi package. Overall, using native packages is the preferred method on platforms supporting this.

Fast Track Configuration

This is the fast track. If running into troubles, look into next chapter Full Configuration. This track assumes that you are using:

• ipv4 addresses.

• Mainstream address options.

• A packaged version running as the ddupdate user (the regular packaging on Fedora, Mageia, Ubuntu and Debian does).

Start with running ddupdate –list-services. Pick a supported service, check it using ddupdate –help <service> and register with the relevant site. This should end up with a hostname, a user and a secret password (some sites just uses an API key).

Then, start the configuration script ddupdate-config. The script guides you through the configuration and updates several files, notably /etc/ddupdate.conf and ~ddupdate/.netrc.

Full Configuration

Configuration is basically about selecting a plugin for a specific ddns service and another plugin which provides the ip address to be registered. Some plugins needs specific plugin options.

The address plugin to use is normally either default-web-ip or default-if.

The default-web-ip plugin should be used when the address to register is the external address visible on the internet - that is, if the registered host should be accessed from the internet. For most services ip-disabled could be used instead. Services will then use the external address as seen from the service. See the ddupdate –help <service> info.

The default-if plugin uses the first address found on the default interface. This typically means registering the address used on an internal network, and should be used if the registered host should be accessed from this internal network.

Should these options not fit, several other address plugins are available using ddupdate –list-addressers. After selecting address plugin, test it using something like:

$ ./ddupdate --ip-plugin default-web-ip --service-plugin dry-run
dry-run: Using
    v4 address: 83.255.182.111
    v6 address: None
    hostname: host1.nowhere.net

After selecting the address plugin, start the process of selecting a service by listing all available services (your list might differ):

$ ddupdate --list-services
changeip             Updates DNS data on changeip.com
dnsexit              Updates DNS data on www.dnsexit.com
dry-run              Debug dummy update plugin
dtdns                Updates DNS data on dtdns.com
duckdns              Updates DNS data on duckdns.org
duiadns              Updates DNS data on duiadns.com
dynu                 Updates DNS data on dynu.com
freedns.afraid       Updates DNS data on freedns.afraid.org
freedns.io           Updates DNS data on freedns.io
no-ip                Updates DNS data on no-ip.com
now-dns              Updates DNS data on now-dns.com
system-ns            Updates DNS data on system-ns.com

Next, pick a service plugin and check the help info, here dynu:

$ ddupdate --help dynu
Name: dynu
Source: /home/al/src/ddupdate/src/ddupdate/plugins/ddplugin.py

Update a dns entry on dynu.com

Supports ip address discovery and can thus work with the ip-disabled
plugin.

.netrc: Use a line like:
    machine api.dynu.com login <username> password <password>

Options:
    none

If all looks good, register on dynu.com. This will end up in a hostname, username and password. Using the .netrc info in the ddupdate help <service>, create an entry in the ~/.netrc file like:

machine api.dynu.com login <username> password <secret>

Note that this file must be protected for other users (otherwise no tools will accept it). Do:

$ chmod 600 ~/.netrc

Now, let’s select the plugin which provides the ip address to register. For the default case, the default-web-ip plugin generates the address as seen from the network. Test the service using the selected address plugin, something like:

$ ./ddupdate --address-plugin default-web-ip --service-plugin dynu \
--hostname myhost.dynu.net -l info
INFO - Loglevel: INFO
INFO - Using hostname: myhost.dynu.net
INFO - Using ip address plugin: default-web-ip
INFO - Using service plugin: dynu
INFO - Plugin options:
INFO - Using ip address: 90.3.08.212
INFO - Update OK

When all is fine, update ~/.config/ddupdate.conf or /etc/ddupdate.conf to something like:

[update]
address-plugin = web-default-ip
service-plugin = dynu
hostname = myhost.dynu.net
loglevel = info

After which it should be possible to just invoke ddupdate without any options.

Configuring systemd

If using a packaged version: make your ~/.netrc available for the user running the service by copying it to the ddupdate user’s home and give it proper permissions (have you been using ddupdate-config this is already done):

sudo cp ~/.netrc ~ddupdate
sudo chmod 600 ~ddupdate/.netrc
sudo chown ddupdate ~ddupdate/.netrc

Again, using a packaged version just test the service and the logged info:

$ sudo systemctl daemon-reload
$ sudo systemcl start ddupdate.service
$ sudo journalctl -u ddupdate.service

If all is fine make sure ddupdate is run hourly using:

$ sudo systemctl start ddupdate.timer
$ sudo systemctl enable ddupdate.timer

If there is trouble, the safest bet is not to use the upstream systemd files. Do:

$ sudo cp /lib/systemd/system/ddupdate* /etc/systemd/system

Check the two /etc files, in particular for paths. Test the service and the logged info as described above.

Configuring NetworkManager

NetworkManager can be configured to start/stop ddupdate when interfaces goes up or down. An example script to drop in /etc/NetworkManager/dispatcher.d is distributed in te package.