INADYN(8)

NAME
inadyn - Internet Automated Dynamic DNS Client

SYNOPSIS
inadyn [-1, --once] [--cache-dir=PATH] [-c, --cmd=/path/to/cmd] [-C, --continue-on-error] [-e, --exec=/path/to/cmd] [-f, --config=FILE] [-h, --help] [-i, --iface=IFNAME] [-I, --ident=NAME] [-l, --loglevel=LEVEL] [-n, --foreground] [-P, --pidfile=FILE] [-p, --drop-privs=USER[:GROUP]] [-s, --syslog] [-t, --startup-delay=SEC] [-v, --version]

DESCRIPTION
inadyn, or In-a-Dyn, periodically checks your actual Internet accessible IP for changes. When it changes inadyn updates your name server record(s) automatically.

Common DDNS service providers supported by inadyn are listed below. Some of these services are free of charge for non-commercial use, others take a small fee, but also provide more domain names to choose from.

inadyn defaults to HTTPS for all providers, some may however not support this so try disabling SSL for your provider in case of problems. Providers known to support SSL updates are listed below with https:

•   <http://www.dyndns.org> a.k.a. <http://dyn.com>
•   <https://freedns.afraid.org>
•   <https://zoneedit.com>
•   <http://www.no-ip.com>
•   <http://www.easydns.com>
•   <http://www.tzo.com>
•   <http://www.3322.org>
•   <https://www.dnsomatic.com>
•   <http://www.tunnelbroker.net>
•   <http://dns.he.net>
•   <http://www.dynsip.org>
•   <http://www.sitelutions.com>
•   <http://www.dnsexit.com>
•   <http://www.changeip.com>
•   <http://www.zerigo.com>
•   <http://www.dhis.org>
•   <https://nsupdate.info>
•   <https://duckdns.org>
•   <https://www.loopia.com>
•   <https://www.namecheap.com>
•   <https://domains.google.com>
•   <https://www.ovh.com>
•   <https://www.dtdns.com>
•   <http://giradns.com>
•   <https://www.duiadns.net>
•   <https://ddnss.de>
•   <http://dynv6.com>
•   <http://ipv4.dynv6.com>
•   <https://spdyn.de>
•   <https://www.strato.com>

DDNS providers not listed here, like <http://twoDNS.de>, can often be configured using the generic DDNS provider plugin. See inadyn.conf(5) for example configurations.

OPTIONS
Earlier versions of inadyn supported more command line options, from v2.0 inadyn has been greatly simplified. See inadyn.conf(5) for details of the /etc/inadyn.conf configuration file format.

-1, --once
    Force one update and quit

--cache-dir=PATH
    Set directory for persistent cache files, defaults to /var/cache/inadyn

    The cache files are used to keep track of which addresses have been successfully sent to their respective DDNS provider and when. The latter 'when' is important to prevent inadyn from banning you for excessive updates.

    When restarting inadyn or rebooting your server, or embedded device, inadyn reads the cache files to seed its internal data structures with the last sent IP address and when the update was performed. It is therefore very important to both have a cache file and for it to have the correct time stamp. The absence of a cache file will currently cause a forced update.

    On an embedded device with no RTC, or no battery backed RTC, it is strongly recommended to pair this setting with the --startup-delay=SEC command line option.

-c, --cmd=/path/to/cmd [optional args]
    Full path to command, or script, to run to check for IP address change. This is the same as the configuration file option checkip-command but will apply to all providers. This command line option is only provided for convenience, it is recommended to instead use the configuration file. For more details, see the inadyn.conf(5) man page. You will need to quote the complete command if any arguments, or pipe, is given.

--continue-on-error
    Ignore errors from DDNS provider and try again later. This command line option tells inadyn to not exit on errors from a DDNS provider and instead try again later. Please do not use this, it usually indicates that we are sending a malformed request, e.g. wrong username, password or DNS alias for the given account. Continuing could possibly lock you out of your account!

-e, --exec=/path/to/cmd [optional args]
    Full path to command, or script, to run after a successful DDNS update. The following environment variables are set: INADYN_IP, INADYN_HOSTNAME. The first environment variable contains the new IP address, the second the host name alias. The cmd is called for each listed host name that is successfully updated. If inadyn is started with the -i IFNAME command line option, the INADYN_IFACE environment variable is also set. You will need to quote the complete command if any arguments, or pipe, is given.

-f, --config FILE
    Use FILE for configuration. By default /etc/inadyn.conf, is used. See inadyn.conf(5) for examples.

-h, --help
    Show summary of command line options and exit

-i, --iface IFNAME
    Check IP of IFNAME instead of querying an external server. With this command line option the external IP check is disabled and inadyn will report the IP address of IFNAME to all DDNS providers listed in the configuration file. This can be useful to register LAN IP addresses, or, when connected directly to a public IP address, to speed up the IP check if the DDNS provider's check-ip servers are slow to respond.

    This option can also be given as a configuration option in inadyn.conf(5), both serve a purpose, use whichever one works for you.

-I, --ident=NAME
    Specify program identity (name) to be used for PID file and syslog messages. Useful with multiple instances of inadyn, or to simply replace the inadyn name with something more generic, e.g. "DDNS", without renaming the binary. Note, this option only changes the base name of the PID file, not the location, which is system specific. Usually /var/run/inadyn.pid or /run/inadyn.pid.

-l, --loglevel LEVEL
    Set log level: none, err, info, notice, debug. The default is notice, but you might want to set this to -l warning.

-n, --foreground
    Run in foreground, default is to daemonize and continue in the background. This option is usually required when running under process supervisors like systemd and Finit. Remember to also give the -s option to get log messages to the syslog.

-p, --drop-privs=USER[:GROUP]
    Drop root privileges after initial setup to the given user and group.

-P, --pidfile=FILE
    Set PID file name and location, defaults to /run/inadyn.pid, which is derived from --ident=NAME, which is strongly recommended to change over this option. However, some users want to keep application runtime files in separate directories, usally in combination with --drop-privs, for such cases this is the option to use.

-s, --syslog
    Use syslog(3) for log messages, warnings and error conditions. This is the default when running in the background. When running in the foreground, see -n, log messages are printed to stdout.

-t, --startup-delay SEC
    Initial startup delay. Default is 0 seconds. Any signal can be used to abort the startup delay early, but SIGUSR2 is the recommended to use. See SIGNALS below for full details of how inadyn responds to signals.

    Intended to allow time for embedded devices without a battery backed real time clock to set their clock via NTP at bootup. This is so that the time since the last update can be calculated correctly from the inadyn cache file and the forced-update=SEC setting honored across reboots, avoiding unnecessary IP address updates.

-v, --version
    Show program version and exit.

OUTPUT
inadyn prints a message when the IP is updated. If no update is needed then by default it prints a single “”. character, unless --loglevel is set to none. Therefore, unless --loglevel is set to none, the log will contain lots of dots. When the connection goes down inadyn may print some harmless error messages which should be followed by “OK” messages after the Internet connection is restored.

SIGNALS
inadyn responds to the following signals:

HUP Reload the .conf file, standard UNIX behavior
TERM
    Tell inadyn to exit gracefully
INT Same as TERM
USR1
    Force update now, even if the IP address has not changed. Works in tandem with --fake-address
USR2
    Check IP address change now. Useful when a new DHCP/PPPoE lease or new gateway is received. Please note that inadyn does not track such events by itself. You need an external monitor for that

For convenience in sending signals, inadyn writes its process ID to /var/run/inadyn.pid

FILES
/etc/inadyn.conf
/run/inadyn.pid
/var/cache/inadyn/dyndns.org.cache
/var/cache/inadyn/freedns.afraid.org.cache
... one .cache file per DDNS provider

SEE ALSO
inadyn.conf(5)

The inadyn home page is at GitHub: <https://github.com/troglobit/inadyn>

AUTHORS
inadyn was originally written by Narcis Ilisei <mailto:inarcis2002@hotpop.com> and Steve Horbachuk. Current patch monkey is Joachim Nilsson <mailto:troglobit@gmail.com> with a lot of help from Andrey Tikhomirov and Mike Fleetwood.

This manual page was originally written for the Debian GNU/Linux project by Shaul Karl <mailto:shaul@debian.org>, but is now maintained by Joachim Nilsson.