connecting my own flashed modem to my IP
 

I'm thinking about flashing an old modem, or buying one that is already set up with dd-wrt, or tomato. I want to connect by means of a vpn. It's a brand new area of study for me, and I don't want to waste money on something that won't work for me. We'll need to use it in our home in the USA, but also, part of each year in Mexico.

Either way we'll need to connect to a local IP, and they always supply their preconfigured modem. if I have my own, do I just plug it into theirs? or reconfigure mine?

Also, is this the best forum to deal with this? If not, can someone point me to a better one for someone like me that is starting from zero on this subject.

Your referring to a router vs a MODEM. The MODEM (Modulator/Demodulator) in a nutshell converts the incoming broadband signal i.e DSL, cable etc to ethernet and therefore dependent on the service provided. Some services use a MODEM/router combination.

So what are you actually trying to accomplish?

I guess you are right that there is a modem separate from the router, but my experience both in Arizona and in Mexico has been that when I go to set-up an agreement with a company to provide me with internet service, they have provided me with a combination modem/router.

What I am trying to accomplish is to set up a fast and private connection from my house (in Arizona, or Mexico) with an IP or VPN or Proxy in the United States.

Swapping MODEMs in the US isn't an option since most require the device to be registered. Adding an additional router might work but I believe for a hardware site to site VPN to work you would need to bridge the first which would require the admin password. No idea what happens in Mexico.

Several ways to connect via linux or windows to a VPN server. You can even use ssh.
I'm sure others will provide more suggestions.