It would be helpful to have a dynamic DNS client included in the RF600VPN, are there plans to include a client? Which client software do you recommend?

Yes, we are planning to add a Dynamic DNS client in the RF600 / RF660. The client will be integrated into our software, so you will not need to run any external client software. For now, you need to use a third party client software and run it on a LAN PC.

DeeEnEs is simplest and it is has a very small foot print.