Black Cat got another query today about offering dynamic DNS to customers. We've had people ask us about it in the past, but the DNS changes we made a while back means it's something that is possibly easier for us to offer now. So I had a think about authentication and tying it in to our current DNS interface and bits like that and decided it might not actually be too hard to get a basic service running.
Then I went and had a look at current implementations. In particular I wanted to see about client support. So I grabbed ez-ipudate, which is used on at least the Netgear DG834G and Linksys WAG54G routers. It supports a load of different services. And the only one that protects the password is GnuDIP. Various services offer HTTPS updates, but ez-ipupdate doesn't support it that I could tell.
I stopped looking at that point. If one of the most common clients doesn't care about protecting users then I don't want to depress myself by finding out how many others don't either. It's a real shame though, as it means if we want to implement dynamic DNS that'll work with standard clients we have to add another authentication system that is unique to that service.