Provided by: inadyn_2.8.1-1_amd64 
NAME
inadyn — Internet Automated Dynamic DNS Client
SYNOPSIS
inadyn [-1, --once] [--force] [--cache-dir PATH] [-c, --cmd /path/to/cmd] [-C, --continue-on-error]
[-e, --exec /path/to/cmd] [--exec-mode MODE] [-f, --config FILE] [-h, --help] [-i, --iface IFNAME]
[-I, --ident NAME] [-l, --loglevel LEVEL] [-n, --foreground] [--no-pidfile] [-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:
• ⟨https://freedns.afraid.org⟩
• ⟨https://nsupdate.info⟩
• ⟨https://duckdns.org⟩
• ⟨https://freemyip.com⟩
• ⟨https://www.loopia.com⟩
• ⟨http://www.dyndns.org⟩, ⟨http://dyn.com⟩
• ⟨http://www.noip.com⟩
• ⟨http://www.easydns.com⟩
• ⟨http://dns.he.net⟩
• ⟨http://www.tunnelbroker.net⟩
• ⟨https://www.dnsomatic.com⟩
• ⟨http://www.sitelutions.com⟩
• ⟨http://www.dnsexit.com⟩, parent of ⟨https://zoneedit.com⟩
• ⟨http://www.changeip.com⟩
• ⟨http://www.dhis.org⟩
• ⟨https://www.namecheap.com⟩
• ⟨https://domains.google⟩
• ⟨https://www.ovh.com⟩
• ⟨http://giradns.com⟩
• ⟨https://www.duiadns.net⟩
• ⟨https://ddnss.de⟩
• ⟨http://dynv6.com⟩
• ⟨http://ipv4.dynv6.com⟩
• ⟨https://spdyn.de⟩
• ⟨https://www.cloudxns.net⟩
• ⟨https://www.pubyun.com⟩, formerly ⟨http://www.3322.org⟩
• ⟨https://www.dnspod.cn⟩
• ⟨https://www.dynu.com⟩
• ⟨https://www.selfhost.de⟩
• ⟨https://connect.yandex.ru⟩
• ⟨https://www.cloudflare.com⟩
DDNS providers not listed here can often be configured using the generic/custom DDNS provider plugin.
See inadyn.conf(5) for examples.
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
Run only once and quit, updates only if too old or unknown. Use --force to for an update before
exiting.
--force
Force one update. Only works with -1, --once flag, ignored for all other use-cases.
--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. 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. 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.
--exec-mode MODE
Use MODE to set the exec script run mode: compat, event: - compat: run exec handler on successful
DDNS update only, default - event: run exec handler on any update status The following
environment variables are set: INADYN_EVENT, INADYN_ERROR, INADYN_ERROR_MESSAGE. INADYN_EVENT
contains the event, one of: nochg, update, error. The event nochg indicates that no update had
to be sent, the event update indicates that an update was sent successully, the event error
indicates that the update was sent and an error occurred. INADYN_ERROR contains the error code,
INADYN_ERROR_MESSAGE contains the error message for the error code.
-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, but is also
useful when running from the terminal, when debugging a config or at initial set up. Remember to
also give the -s option if you still want to redirect log messages to the syslog.
-p, --drop-privs USER[:GROUP]
Drop root privileges after initial setup to the given user and group.
--no-pidfile
When running as a daemon, even when running in the foreground with -n, inadyn creates a PID file
so users can easily find the PID of the process to send signals to. See “SIGNALS” for more
information on this. This option tells inadyn to not create a PID file. Some users prefer this
when running under systemd.
-P, --pidfile FILE
Set PID file name and location, defaults to /run/inadyn.pid, 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, usually 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
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, unless the
--ident NAME option is used.
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⟩, and is currently maintained by Joachim Nilsson.
Debian February 20, 2020 INADYN(8)