IP Update API¶
In case you want to dig deeper, here are the details on how our IP update API works. We provide this API to be compatible with most dynDNS clients. However, we also provide a RESTful API that is more powerful and always preferred over the legacy interface described here.
Please note that when using HTTPS (which we highly recommend), outdated setups (such as TLS < 1.2) are not supported. If you encounter SSL/TLS handshake issues, you may have to update your dynDNS client and/or libraries used by it (such as OpenSSL).
Note: Out of mercy for legacy clients (especially old routers), we still accept unencrypted requests for this service. We urge you to use HTTPS whenever possible.
An IP update is performed by sending a
GET request to
via IPv4 or IPv6. To enforce IPv6, use
update6.dedyn.io. The path
component can be chosen freely as long as it does not end in
.png. HTTPS is recommended over HTTP.
When the request is authenticated successfully, we use the connection IP
address and query parameters to update your domain’s DNS
A (IPv4) and
AAAA (IPv6) records. The new records will have a TTL value of 60 seconds
(that is, outdated values should disappear from DNS resolvers within that
IP Update Authentication¶
You can authenticate your client in several ways. If authentication fails, the
API will return a
401 Unauthorized status code.
Preferred method: HTTP Basic Authentication (with token)¶
Encode your username and token (provided during registration) in the
Authorization: Basic ... header. This is the method virtually all dynDNS
clients use out of the box.
Important: If your dynDNS client asks for a password, do not enter your account password (if you have one). Instead, enter your token!
HTTP Token Authentication¶
Authorization: Token ... header along with your request, where
... is the token issued at registration (or manually created later).
Query string method (discouraged)¶
password query string parameters (
Important: We strongly discourage using this method as it comes with a subtle disadvantage: We log all HTTP request URLs for a few days to facilitate debugging. As a consequence, this method will cause your secret token to end up in our log files in clear text. The method is provided as an emergency solution where folks need to deal with old and/or crappy clients. If this is the case, we suggest looking for another client.
To update your IP address in the DNS, our servers need to determine the hostname you want to update. To determine the hostname, we try the following steps until there is a match:
hostnamequery string parameter, unless it is set to
YES(this sometimes happens with dynDNS update clients).
host_idquery string parameter.
- The username as provided in the HTTP Basic Authorization header.
- The username as provided in the
usernamequery string parameter.
- After successful authentication (no matter how), the only hostname that is associated with your user account (if not ambiguous).
If we cannot determine a hostname to update, the API returns a status code of
400 Bad Request (if no hostname was given but multiple domains exist in
the account) or
404 Not Found (if the specified domain was not found).
The dynDNS update API can also be used to update IP records for subdomains. To do so, make sure that in the above list of steps, the first value provided contains the full domain name (including the subdomain).
Example: Your domain is
yourdomain.dedyn.io, and you’re using HTTP Basic
Authentication. In this case, replace your authentication username with
sub.yourdomain.dedyn.io. Similarly, if you use the
parameter, it needs to be set to the full domain name (including subdomain).
To update more than one domain name, please see Updating multiple domains.
Determine IP addresses¶
The last ingredient we need for a successful update of your DNS records is your
IPv4 and/or IPv6 addresses, for storage in the
For IPv4, we will use the first IPv4 address it can find in the query string
ip (in this order). If none of them is
set, it will use the IP that connected to the API, if a IPv4 connection was
made. If no address is found or if an empty value was provided instead of an IP
A record will be deleted from the DNS.
For IPv6, the procedure is similar. We check
ip query string parameters (in this order) and the IP that was used to
connect to the API for IPv6 addresses and use the first one found. If no
address is found or an empty value provided instead, the
AAAA record will
If successful, the server will return a response with status
200 OK and
good as the body (as per the dyndns2 protocol specification). For error
status codes, see above.
dynDNS updates are subject to rate limiting. For details, see Rate Limits.
The examples below use
<your domain> as the domain which is to be updated
(which could be a custom domain or a dedyn.io domain like
<your authorization token> as an API token
affiliated with the respective account (see Manage Tokens for details.)
22.214.171.124 is used as an example for an IPv4 address,
fd08::1234 as a
stand-in for an IPv6 address. Replace those (including the
with your respective values.
Basic authentication with automatic IP detection (IPv4 or IPv6):
curl --user <your domain>:<your authorization token> https://update.dedyn.io/ curl https://update.dedyn.io/?hostname=<your domain> \ --header "Authorization: Token <your authorization token>"
Basic authentication with forced use of IPv6 (will remove IPv4 address from the DNS):
curl --user <your domain>:<your authorization token> https://update6.dedyn.io/ curl https://update6.dedyn.io/?hostname=<your domain> \ --header "Authorization: Token <your authorization token>"
Basic authentication with simultaneous update of IPv4 and IPv6:
curl --user <your domain>:<your authorization token> \ "https://update.dedyn.io/?myipv4=126.96.36.199&myipv6=fd08::1234" curl "https://update6.dedyn.io/?hostname=<your domain>?myipv4=188.8.131.52&myipv6=fd08::1234" \ --header "Authorization: Token <your authorization token>"