There are countless reports of people who are having trouble configuring their network equipment to work with Dyndns, mostly because they need to enter an IP ADDRESS on their devices, rather than the usual dns name : members.dyndns.org
The forum keeps running around the bush about it. So I will give you a straight and short answer here:
The DynDNS IP number is 188.8.131.52
According to DynDNS the syntax for an HTTP request uses members.dyndns.org. Just open a DOS command prompt and type
The result will reveal the IP address.
Note that it is quite possible that the result will be different from the address stated on top of this post. Especially if they use load balancing on their servers. You can use the one found by me or yours, it should work in both cases.
Another note: This is crucial to configure the I Power IP9258 with DDNS