DynDNS has problems
The free dynamic DNS service of the DynDNS service provider is not functioning correctly at the moment. The server is accepting updates from clients, without issuing an error message, but the new entries do not appear on the DNS server. The servers respond with an outdated entry as an IP address for a DynDNS name.
Using the dynamic nameserver service from DynDNS, a fixed host name can be assigned to a computer with a dynamic IP address allocated by the provider. This enables a web server, for example, to be operated, despite a dynamic IP address.
According to reports on the DynDNS forum, the current problem with the updating of IP addresses to DynDNS names started yesterday, Sunday (9th March). Since the wrong addresses are being delivered from the DNS servers at DynDNS and the entries are simply outdated, it appears likely to be a technical fault rather than a hacker attack. DynDNS could not be reached for a statement. Anyone who assigns their IP address to a name via DynDNS can easily check whether they are affected, using two tools at heise networks. The My IP address tool displays your IP address. With DNS query, you can check whether your DynDNS name is resolved to this address, or whether an older address is still held in the DNS.
Evidently, only the API for automatic updates of DNS entries is affected. Manual changes via the provider's web site are correctly assigned by the DNS server.