The DynDNS dynamic update system uses a blocking mechanism to prevent flooding. An update client should only send an update when an IP change is detected; if we receive too many unnecessary updates for a host, the host is blocked and cannot receive additional updates until it is unblocked.

Why was I blocked?

Abuse blocks usually occur when an update client is misbehaving. The most common causes are:

  • Client updates at regular intervals: Clients should only send updates when a change is detected, but some are programmed to send updates at scheduled intervals, (e.g. every five minutes or every hour).
  • Client is malfunctioning: Incorrect installation (e.g., cannot write IP to file), incorrect configuration (e.g., installing a Linux client in cron instead of running as a daemon), or physical problems (e.g., power fluctuations for hardware clients) can cause the client to send abusive updates.
  • Multiple clients: If you install two or more update clients in the same network, such as both a software client and a hardware client, the extra updates will count as abusive.

Please check your update client’s logs to determine why the client has been misbehaving. For more assistance with diagnosing a problem, please contact support.

How do I prevent future blocks?

In most cases, abusive updates are generated by unofficial software clients or non-certified hardware clients. The most effective solution is to replace your update client with one that works correctly:

  • Use an official software client: We offer software-based DynDNS Updater clients for Windows and Mac OS X, and support select third-party clients for Unix-based systems.

Replacing your update client with an official software client or certified hardware client should prevent the host from being blocked in the future. We strongly recommend software clients over hardware clients, as they are easier to troubleshoot, provide more comprehensive logging, and are easier to configure. Only use a hardware client if there is no computer available in the network (e.g., remote DVR at a cabin in the woods).

What is an abusive update?

Any update which assigns the hostname to a new IP address is considered “good”; all other updates are considered unnecessary and therefore “abusive.” It is very difficult to accidentally block a host with manual updates; in almost all cases, a host is blocked due to a malfunctioning or poorly-coded update client.

How do I unblock my host?

When a host becomes blocked for abuse, you should receive an email notification which provides an unblock request link. If you follow the link, it will bring you to a page where you can unblock the host. (You can also find an unblock link on the host’s configuration page in your account.)

Before you unblock the host, please be sure that you have fixed the problem, or contact support for assistance in troubleshooting; if you unblock the host but do not fix the problem, it will simply become blocked again over time.