Internet Automated Dynamic DNS Client

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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As of October 2025, this project has been archived and is no longer maintained.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

Introduction
Supported Providers
Configuration
Custom DDNS Providers
Troubleshooting
Build & Install
Building from GIT
Origin & References

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 config

Inadyn

Install / Use

README