dont have a static ip, whats a good dynamic dns client to use?

I used to use DynDNS, but then they stopped their free service.   Now I use DNSexit. Works fine, no complaints.

noip.com still has a free level (limit 5 hosts for free)...

OOps... Just checked... Free account now has 3 hosts limit per account!

Get a free account here: http://www.noip.com/sign-up

they also supply an auto update software (DUC) installed on your network that will periodically update the ip address on their servers...

See: http://www.noip.com/download?page=win for info on the DUC (Dynamic Update Client)

PS: If you have your own domain, you can still use noip.com with it... Just create a CNAME entry in your DNS that ties the noip dynamic domain to yours... I have done this for years and it works just fine!   And all FREE!

For my home camera system clients i've been having them purchase a domain from NameCheap.com.    Namecheap has a free dynamic DNS service.  It costs my clients about $11 a year to reregister the domain.    Pretty cheap and easy to setup.   The NameCheap tech support is plenty helpful.   To setup a namecheap account and configure the dynamic DNS takes 10 minutes.  

Plus, your hostname ends up being something custom and maybe relevant to you.   i.e. tailoredhomesecurity.com, that's an easy hostname to remember.

After looking through quite a list of DDNS providers, I ended up with Dynu.com and have found the free service able to do what I needed. They had a good-enough explanation of the client requirements for me to get it to work with Tomato firmware on my router even though Tomato didn't know specifically about Dynu.com.

I think it's better if you can get DDNS bundled in with your domain purchase, if you're starting fresh.