[tanguero]

Hello, I would like to set up a VPN from a remote location (which could be anywhere, including in another country), with the following characteristics/requirements. I've attached a diagram that illustrates more clearly what I want. While it seems that this should be a common usage scenario (it would seem that many people away from home, especially travellers, should have any number of reasons to want this), Googling didn't turn up anything exactly like my scenario.

1. Referring to the diagram, my main home location is shown as "Local," connected to ISP "L". That's where I have my Network Attached Storage, my networked Printer, my Plex server, my Roku box, etc., all of which are configured for access only from my "local network" (yes, I know some of these like the Plex server can be configured for access from outside the local network, but that's not the issue here). Router A is my home router connected to my Local ISP "L".

2. I frequently travel, sometimes for weeks at a time, sometimes domestically, sometimes internationally. I always have Internet access via the ISP at my destination (referred to as the Remote ISP "R"). I always have access to the remote router (which I call Router B) to plug in an Ethernet cable, but not to be able to change out the router to a different model (and certainly not to flash its firmware!) and usually not to change any internal router configurations either. But I can connect my own router (Router C) in front of Router B, which is my plan.

3. Assuming the configuration shown in the diagram, then, my requirements are:

a. I would like to be able to connected at will to my "local" network from the remote location from any device that I connect to Router C. Anything connected to Router C should always look to the Internet like its connected directly to Router A (except for bandwidth and latency issues, of course, which may suffer--I realize that every download on the Remote network becomes an additional 1 download + 1 upload on the Local network).

b. Furthermore, all devices connected to Router A and Router C should like like they're all connected to the same local network for the purpose of discovery and access.

c. None of the devices connected to Router C should need any configuration (no VPN software, no proxy servers, etc.) since Router C itself is presumably taking care of that in a way that's transparent to anything connected to it. For simplicity, I'm showing only wired LAN connections, but obviously WLAN connections would work the same way.

d. Ideally, this should need no configuration or change to Router B (which I don't usually have configuration access to).

5. So here are my questions:

a. Is this a valid and workable configuration as shown? With Router A and C being VPN routers and Router B being any router at all? If not, what is a workable configuration that WOULD do what I want?

b. What are the minimum requirements that I need to search for if I want to buy off-the-shelf routers that can do the VPN Sink and Source functions of Routers A and C respectively?

c. Can DD-WRT do this (I assume yes, hence my posting here!). And how do I have to configure it to make it work the way as shown?

d. Do I need a static IP to make this work? Is there a way to make it work without a static IP address? (Neither ISP L nor ISP R gives me a static IP address.)

e. Are there other questions I should be asking and haven't?

Thanks in advance!