VPN Site to Site using Dynamic Public?

Hi guys, I’m trying build a VPN Network, but i can`t find “using Dynamic Public” topics.

Site1
CableModem with DYNDNS and DMZ for RB433 <—> RB433 (DMZ on CableMODEM) <------> LAN

Site2
CableModem with DYNDNS and DMZ for RB433 <—> RB433 (DMZ on CableMODEM) <------> LAN

Somebody know if exist a topic to help to build a VPN, this case, couple Cablemodem’s provide the Public Dynamic IP to RouterBoards because RB433 are into DMZ, Cablemodem’s has configured correctly DYNDNS account and we can access couple RB433 by Winbox, SSH even we can access to other services by port forward (servers or services on LAN).

Appologies by poor english, but i dont like use google translate, because some times change the central idea.

What kind of VPN do you want?

With something simple like SSTP or OpenVPN, it should just work, all you need is the right port forwarded to RB doing server (which you already have in DMZ if I understand it correctly) and client connecting to server’s dyndns hostname. There will be some downtime (depending on hostname’s TTL) when address changes, but I don’t think you can do anything with that.

If you’d like IPSec, it’s probably also doable, but not without some scripting.