Windows 2003 DNS for Dynamic Updates

[Chris]

Hi...

I am trying to setup a Dynamic DNS server dor hosting domains.

I have currently got a windows 2k3 DNS server hosting my domains eg
"mydomain.com" I want to beable to get clients around the country to
update Hosts eg "sales.mydomain.com"

I have managed to find a client which should support this called
DynSite, this client does work from any computer running on the
private side of the network where the Dns server is located however
when i try and update a host from a client in a different location I
just get an error??

One thing i did notice was from the private side of the server I can
telnet to port 53 but from outside I can not, as the update client
used port 53 I was wondering if this wold be causing any problems?

the firewall does allow port 53 through as the server does work for
resolving DNS for the hosted domains.

Can anyone help please

Thanks Chris