Question : Is dynamic fixed IP secure for RDP connections?

In an earlier question: http://www.experts-exchange.com/Security/Encryption/Q_24357605.html
I've asked about securely connecting to clients modem by RDP.

One of the suggestions wee that I use static hostname through dynamic IP. Now, my company use Dyn Inc. for all DNS services, including ones for static host names. - But he expert said he doesn't recommend that.

Hypothetically; if for example I create alskjdnakds2j3dah4fasdjf4229jk29374.domain.tdl, and enable connection to RDP port on the router only from that address (associated with my working computer / internet connection), would the connection be reasonably secure?

If not, why not?


****************FROM THE MENTIONED POST****************
"Is there any secure way to use RDP directly?

Another option would be to limit the access to this port to a static hostname from a dynamic DNS provider (e. g. dyndns.org). That way you could use dynamic IP addresses to access the network.

But I don't recommend that."

Answer : Is dynamic fixed IP secure for RDP connections?

Absolutely fine - and is what most outfits do as standard.