Cable modem dynamic IP addresses tend to not change very often, but DSL changes constantly. I think the DSL service is managed more like dial-up service. If there's no traffic, the connection is dropped. As soon as your end makes a request, the connection is re-established, which usually results in a new IP address assignment.

The Netgear VPN can support a domain name. Newer models have built-in support for dynamic DNS services. So all you have to do is get an account from one of the ones supported (like DynDNS.org) andthe router will take care of updating the DNS host whenever the IP changes.

Rob Cashman
Customer Support Engineer