I just want to know, how to view camera over the internet. I dont have static IP so that can be the problem, because the dynamic ip can be changed and I have to use DDNS. But as I know, the dynamic IP doesnt change so often, so will it works (watch camera through internet) with the nonchanging dynamic IP? Or the DDNS does something more than just updating IP into domain. Thanks a lot.
This might not be the right board for this question, but as I use the same service for various things, I'll take a stab at answering your question.
Services like DynDNS an other DDNS providers exists for the sole reason, as you mentioned, of updating an IP address to a domain name. This is useful in instances, like remote camera viewing, where you may or may not know the WAN IP address of the camera's location.
Usually, cable ISPs will not update your WAN IP address very often, so a DDNS service might not seem like a necessity. That could come back to bite you though if you're traveling and your ISP does update your WAN IP address.
Most DSL ISPs update your WAN IP address fairly often, so in those instances, a DDNS service would be more useful as you would have access to your camera regardless of the WAN IP address where it is located.
So all that said, the real answer comes down to your specific requirements. Hope that helps!