Internet Automated Dynamic DNS Client
Project Archived
As of October 2025, this project has been archived and is no longer maintained.
After many years of development and community contributions, maintenance on this
repository has ended. The source code remains available for reference and for
anyone who wishes to continue development in their own fork.
— Joachim Wiberg (troglobit)
The last release remains available from GitHub at https://github.com/troglobit/inadyn/releases
Table of Contents
Introduction
Tip: the HTML UNIX manual is at https://man.troglobit.com, e.g.,
inadyn.conf(5)
Inadyn, or In-a-Dyn, is a small and simple Dynamic DNS, DDNS, client
with HTTPS support. Commonly available in many GNU/Linux distributions,
used in off the shelf routers and Internet gateways to automate the task
of keeping your Internet name in sync with your public¹ IP address. It
can also be used in installations with redundant (backup) connections to
the Internet.
Most people are unaware they share a pool of Internet addresses with
other users of the same Internet Service Provider (ISP). Protocols like
DHCP, PPPoE, or PPPoA are used to give you an address and a way to
connect to the Internet, but usually not a way for others to connect to
you. If you want to run an Internet server on such a connection you
risk losing your IP address every time you reconnect, or as in the case
of DHCP even when the lease is renegotiated.
By using a DDNS client like inadyn you can register an Internet name
with a DDNS provider, like FreeDNS. The
DDNS client updates your DNS record periodically and/or on demand when
your IP address changes. Inadyn can maintain multiple host records with
the same IP address, use a combination of a script, the address from an
Internet-facing interface, or default to using the IP address change
detector of the DDNS provider.
__
¹ Public IP address is the default, private addresses can also be used.
Supported Providers
Some of these services are free of charge for non-commercial use, some
take a small fee, but also provide more domains to choose from.
The following tier-one providers have dedicated “plugins”, even though
many share the original DynDNS plugin. Below is a list of known DDNS
providers, ordered by the plugin that support them:
For the complete list, see inadyn -L, for machine friendly JSON
output, use inadyn -L -j.
DDNS providers not supported natively can be enabled using the custom,
or generic, DDNS plugin. See below for configuration examples.
In-A-Dyn defaults to HTTPS, but not all providers may support this, so
try disabling SSL for the update (ssl = false) or the checkip phase
(checkip-ssl = false) in the provider section, in case you run into
problems.
HTTPS is enabled by default since it protects your credentials from
being snooped and reduces the risk of someone hijacking your account.
Configuration
In-A-Dyn supports updating several DDNS servers, several accounts even on
different DDNS providers. The following /etc/inadyn.conf example show
how this can be done. To verify your configuration, without starting the
daemon, use:
inadyn --check-config
This looks for the default .conf file, to check any file, use:
inadyn --check-config -f /path/to/file.conf
Example
# In-A-Dyn v2.0 configuration file format
period = 300
user-agent = Mozilla/5.0
# The FreeDNS username must be in lower case
# The password (max 16 chars) is case sensitive
provider freedns {
username = lower-case-username
password = case-sensitive-pwd
hostname = some.example.com
}
# We override checkip server with the In-a-dyn built-in 'default',
# http://ifconfig.me/ip, for details on this, see below.
provider freemyip {
password = YOUR_TOKEN
hostname = YOUR_DOMAIN.freemyip.com
checkip-server = default
}
provider dyn {
ssl = false
username = charlie
password = snoopy
hostname = { peanuts, woodstock }
user-agent = Mozilla/4.0
}
provider duckdns.org {
username = YOUR_TOKEN
password = noPasswordForDuckdns
hostname = YOUR_DOMAIN.duckdns.org
}
# With multiple usernames at the same provider, index with :#
provider no-ip.com:1 {
username = ian
password = secret
hostname = flemming.no-ip.com
user-agent = inadyn/2.2
}
# With multiple usernames at the same provider, index with :#
provider no-ip.com:2 {
username = james
password = bond
hostname = spectre.no-ip.com
checkip-ssl = false
checkip-server = ifconfig.me
checkip-path = /ip
}
# With multiple usernames at the same provider, index with :#
provider no-ip.com:3 {
username = spaceman
password = bowie
hostname = spaceman.no-ip.com
checkip-command = "/sbin/ifconfig eth0 | grep 'inet6 addr'"
}
# Google Domains - notice use of '@' to update root entry
provider domains.google.com:1 {
hostname = @.mydomain.com
username = your_username
password = your_password
}
# Wildcard subdomains - notice the quotes (required!)
provider domains.google.com:2 {
hostname = "*.mydomain.com"
username = your_username
password = your_password
}
# Note: hostname == update-key from Advanced tab in the Web UI
provider tunnelbroker.net {
username = futurekid
password = dreoadsad/+dsad21321 # update-key-in-advanced-tab
hostname = 1234534245321 # tunnel-id
}
# dynv6.com update using a custom checkip-command, which works
# if you have access to an Internet-connected interface. Make
# sure to verify the command works on your system first
allow-ipv6 = true # required option for IPv6 atm.
provider dynv6.com {
username = your_token
password = not_used
hostname = { host1.dynv6.net, host2.dynv6.net }
checkip-command = "/sbin/ip -6 addr | grep inet6 | awk -F '[ \t]+|/' '{print $3}' | grep -v ^::1 | grep -v ^fe80"
}
provider cloudxns.net {
username = your_api_key
password = your_secret_key
hostname = yourhost.example.com
}
provider dnspod.cn {
username = your_api_id
password = your_api_token
hostname = yourhost.example.com
}
# Create a unique custom API token with the following permissions:
# -> Zone.Zone - Read, Zone.DNS - Edit.
provider cloudflare.com {
username = zone.name
password = api_token_important_read_comment
hostname = hostname.zone.name
ttl = 1 # optional, value of 1 is 'automatic'.
proxied = false # optional.
}
provider goip.de {
username = user.name
password = user.password
hostname = hostname.zone.name
}
Notice how the config has three different users of the No-IP provider –
this is achieved by appending a :ID to the provider name.
We also define a custom cache directory, default is to use /var/cache.
In our case /mnt is a system specific persistent store for caching
your IP address as reported to each provider. Inadyn use this to ensure
you are not locked out of your account for excessive updates, which may
happen if your device Internet gateway running inadyn gets stuck in a
reboot loop, or similar.
However, for the caching mechanism to be 100% foolproof the system clock
must be set correctly – if you have issues with the system clock not
being set properly at boot, e.g. pending receipt of an NTP message, use
the command line option --startup-delay=SEC. To tell inadyn it is
OK to proceed before the SEC timeout, use SIGUSR2.
The last system defined is the IPv6 https://tunnelbroker.net service
provided by Hurricane Electric. Here hostname is set to the tunnel ID
and password must be the Update key found in the Advanced
configuration tab.
Note: the checkip-command for dynv6, above, is just one way to
do it. Here’s another variant, from their own script: ip -6 addr list scope global $device | grep -v " fd" | sed -n 's/.*inet6 \([0-9a-f:]\+\).*/\1/p' | head -n 1
Sometimes the default checkip-server for a DDNS provider can be slow
to respond, even time out. In-a-Dyn support overriding the provider’s
default with a custom one, or a custom command. The easiest way to
change it is to set checkip-server = default in you provider config,
triggering In-a-Dyn to use the default http://ifconfig.me/ip, which
also is the default for any custom DDNS configuration. See the man
pages, or the below section, for more information.
Some providers require using a specific browser to send updates, this
can be worked around using the user-agent = STRING setting, as shown
above. It is available both on a global and on a per-provider level.
NOTE: In a multi-user server setup, make sure to chmod your .conf
to 600 (read-write only by you/root) to protect against other users
reading your DDNS server credentials.
Custom DDNS Providers
In addition to the default DDNS providers supported by Inadyn, custom
DDNS providers can be defined in the config file. Use custom {} in
instead of the provider {} section used in examples above.
In-A-Dyn use HTTP basic authentication (base64 encoded) to communicate
username and password to the server. If you do not have a username
and/or password, you can leave these fields out. Basic authentication,
will still be used in communication with the server, but with empty
username and password.
A custom DDNS provider can be setup like this:
custom example {
username = myuser
password = mypass
checkip-server = checkip.example.com
checkip-path = /
ddns-server = update.example.com
ddns-path = "/update?hostname="
hostname = myhostname.example.net
}
The following variables can be substituted into the configuration:
%u - username
%p - password, if HTTP basic auth is not used
%h - hostname
%i - IP address
For https://www.namecheap.com it can look as follows. Notice how the
hostname syntax differs from above:
custom namecheap {
username = YOURDOMAIN.TLD
password = mypass
ddns-server = dynamicdns.park-your-domain.com
ddns-path = "/update?domain=%u&password=%p&host=%h&ip=%i"
hostname = { "@", "www", "test" }
ddns-response = "<ErrCount>0</ErrCount>"
}
Here three hostnames are updated, one HTTP GET update request for every
listed hostname. Some providers, like FreeDNS, support setting up CNAME
records (aliases) to reduce the amount of records you need to update.
FreeDNS even default to linking multiple records to the same update,
which may be very confusing if you want each DNS record to be updated
from a unique IP address – make sure to check your settings at the
DDNS provider!
The generic plugin can also be used with providers that require the
client’s new IP address in the update request. Here is an example of
how this can be done if we pretend that http://dyn.com is not
supported by inadyn. The ddns-path differs between providers and is
something you must figure out. The support pages sometimes list this
under an API section, or similar.
# This emulates dyndns.org
custom dyn {
username = DYNUSERNAME
password = DYNPASSWORD
ddns-server = members.dyndns.org
ddns-path = "/nic/update?hostname=%h.dyndns.org&myip=%i"
hostname = { YOURHOST, alias }
}
Here a fully custom ddns-path with format specifiers are used, see the
inadyn.conf(5) man page for details on this.
Another example:
# Custom configuration for dnsmadeeasy
custom dyn {
username = DNSMADEEASYUSERNAME
password = DNSMADEEASYPASSWORDFORTHISHOST
ddns-server = cp.dnsmadeeasy.com
ddns-path = "/servlet/updateip?username=%u&password=%p&id=DNSMADEEASYHOSTID&ip=%i"
hostname = HOST
}
When using the generic plugin you should first inspect the response from
the DDNS provider. By default Inadyn looks for a 200 HTTP response OK
code and the strings "good", "OK", "true", "success", or "updated" in the
HTTP response body. If the DDNS provider returns something else you can
add a list of possible ddns-response = { Arrr, kilroy }, or just a
single ddns-response = Cool – if your provider does give any response
then use ddns-response = "".
If your DDNS provider does not provide you with a checkip-server, you
can use other services, like http://ifconfig.me/ip, which is the default
if you do not specify one for your custom provider config:
checkip-server = ifconfig.me
checkip-path = /ip
checkip-ssl = false
or even use a script or command:
checkip-command = /sbin/ifconfig eth0 | grep 'inet addr'
These two settings can also be used in standard provider{} sections.
Note: hostname is required, even if everything is encoded in the
ddns-path! The given hostname is appended to the ddns-path used for
updates, unless you use the append-myip setting, in which case your IP
address will be appended instead. When using append-myip you probably
need to encode your DNS hostname in the ddns-path instead, as is done
in the last example above.
Troubleshooting
A common problem is getting started, which is understandable since In-a-Dyn
has a lot of confusing options.
Initial Connection
Having saved your /etc/inadyn.conf, first try starting it in the
foreground with full debug logs:
inadyn -l debug --foreground --force
Any misconfiguration or bad server responses should be a lot easier to
spot. Remember to censor your logs from any passwords and domain info
if you file a bug report or ask a question in the forum/irc!
Not Updating
Try clearing the cache:
sudo systemctl stop inadyn.servicesudo rm -rf /var/cache/inadyn/*sudo systemctl restart inadyn.service
Build & Install
Debian/Ubuntu/Mint
For a long time, the project maintained its own .deb packaging and
basic apt infrastructure. However, the increasing level of features in
In-a-Dyn, and thus amount of dependencies, as well as the demands for
supporting more architectures and different distributions, the pre-built
.deb support has been discontinued as of v2.9.1.
The Debian project now has an active maintainer for inadyn, which is the
upstream for Ubuntu and others. Please report issues and requests to
your respective distribution:
Note: the project’s packaging files have been moved to a separate
debian branch in the GIT repository. It is not actively updated
or supported for releases. To use it, check out the branch and edit
debian/changelog) to build new .deb files for your system.
Docker
Automatically built images available here:
A Dockerfile is provided to simplify building and running inadyn.
docker build -t inadyn:latest .
docker run --rm -v "$PWD/inadyn.conf:/etc/inadyn.conf" inadyn:latest
Periodic Update with Cron
If you don’t want to run In-a-dyn as a background daemon, you can set up
a cronjob:
- Create your
inadyn.conf file
- Create folder for cache
- Add the following line inside crontab
crontab -e
* * * * * docker run --rm -v "path/to/inadyn.conf:/etc/inadyn.conf" -v "path/to/cache:/var/cache/inadyn" troglobit/inadyn:latest -1 --cache-dir=/var/cache/inadyn > /dev/null 2>&1
Homebrew (macOS)
To run the latest stable version on macOS, type:
brew install inadyn
To run the latest version from the master branch, install the git tap instead:
brew install --HEAD troglobit/inadyn/inadyn
Either of these will install all dependencies.
MacPorts (macOS)
You can also install In-A-Dyn on macOS using MacPorts:
sudo port install inadyn
You can find more information at In-A-Dyn’s ports page.
Building from Source
First download the latest official In-A-Dyn release from GitHub:
In-A-Dyn requires a few libraries to build. The build system searches
for them, in their required versions, using the pkg-config tool:
They are available from most UNIX distributions as pre-built packages.
Make sure to install the -dev or -devel package of the distribution
packages when building Inadyn. On Debian/Ubuntu (derivatives):
$ sudo apt install gnutls-dev libconfuse-dev
To build you also need a C compiler, the pkg-config tool, and make:
$ sudo apt install build-essential pkg-config
When building with HTTPS (SSL/TLS) support, make sure to also install
the ca-certificates package on your system, otherwise Inadyn will not
be able to validate the DDNS provider’s HTTPS certificates.
The GNU Configure & Build system use /usr/local as the default install
prefix. In many cases this is useful, but this means the configuration
files and cache files will also use that same prefix. Most users have
come to expect those files in /etc/ and /var/run/ and configure has
a few useful options that are recommended to use:
$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make -j5
$ sudo make install-strip
You may want to remove the --prefix=/usr option.
SSL/TLS Support
By default inadyn tries to build with GnuTLS for HTTPS support. GnuTLS
is the recommended SSL library to use on UNIX distributions which do not
provide OpenSSL/LibreSSL as a system library. However, when OpenSSL or
LibreSSL is available as a system library, for example in many embedded
systems:
./configure --enable-openssl
To completely disable inadyn HTTPS support (not recommended!):
./configure --disable-ssl
For more details on the OpenSSL and GNU GPL license issue, see:
Static Build
Some people want to build statically, to do this with autoconf add the
following LDFLAGS= after the configure script. You may also need to
add LIBS=..., which will depend on your particular system:
./configure LDFLAGS="-static" ...
RedHat, Fedora, CentOS
On some systems the default configure installation path, /usr/local,
is disabled and not searched by tools like ldconfig and pkg-config.
So if configure fails to find the libConfuse libraries, or the .pc
files, create the file /etc/ld.so.conf.d/local.conf with this content:
/usr/local/lib
update the linker cache:
sudo ldconfig -v |egrep libconfuse
and run the Inadyn configure script like this:
PKG_CONFIG_PATH=/usr/local/lib/pkgconfig ./configure
Integration with systemd
For systemd integration you need to install pkg-config, which helps
the Inadyn build system figure out the systemd paths. When installed
simply call systemctl to enable and start inadyn:
$ sudo systemctl enable inadyn.service
$ sudo systemctl start inadyn.service
Check that it started properly by inspecting the system log, or:
$ sudo systemctl status inadyn.service
To stop the service:
$ sudo systemctl stop inadyn.service
Embedded applications
When built into a router, some features aren’t usually used and can be disabled
to save space. The configure option --enable-reduced will build such a
reduced-functionality binary. Currently, this disables verbose log messages and
error strings and eliminates config file checking & some backward compatibility.
Building from GIT
If you want to contribute, or simply just try out the latest but
unreleased features, then you need to know a few things about the
GNU build system:
configure.ac and a per-directory Makefile.am are key filesconfigure and Makefile.in are generated from autogen.sh,
they are not stored in GIT but automatically generated for the
release tarballsMakefile is generated by configure script
To build from GIT; clone the repository and run the autogen.sh script.
This requires the GNU tools automake, autoconf and libtool to be
installed on your system. Released tarballs do not require these tools.
$ sudo apt install git automake autoconf
Then you can clone the repository and create the configure script,
which is not part of the GIT repo:
git clone https://github.com/troglobit/inadyn.git
cd inadyn/
./autogen.sh
./configure && make
Building from GIT requires, at least, the previously mentioned library
dependencies. GIT sources are a moving target and are not recommended
for production systems, unless you know what you are doing!
Origin & References
This is the continuation of Narcis Ilisei’s original INADYN. Now
maintained by Joachim Wiberg. Please file bug reports, or send
pull requests for bug fixes and proposed extensions at GitHub.
A personal Thank you! goes out to Robert Högberg, who sponsored a
little D-Link DIR-645 router so I could get back on the interwebs :-)
评论