How can I setup a large ddns service environment with Bind9?

[won seok]

"Hans Spaans" <cj.spaans at nexit.nl> wrote in message news:<c9usan$v39$1 at sf1.isc.org>...
> won seok said:
> > I would like to setup a ddns server that can provide the ddns service
> > to a few thousands of clients.
> > I want to know that the bind9 can be a proper solution for this
> > condition.
> > If so what operations should I do?
> > As I known, the bind9 software require that same authentification key
> > should be located at client and server simultaneously. If any
> > administrator want to provide the ddns service to one thousand of
> > clients, should the server maintain one thousand of authentification
> > keys ?
> > I look forward to any help.
> > Thanks in advance.
> 
> Why don't you let the DHCP-servers update DNS instead of your clients? And
> for Windows Domain Controllers, if you have them, you can give them access
> based on IP.
> 
> Hans

I'm afraid I didn't explain enough the service environment. 
At first the ddns service will be provided on internet environment. I
can't get any help of a DHCP server. And moreover, I must distinguish
any user's update request and any hacker's attack.
And the ddns server and client are linux based systems. 

I wonder there is needed to implement any software module that
securely distinguish a lot of client's request.
If anyone have helpful material to me, please response to me. 
Thank you very much.