I have two Linodes in the same data center. I want to copy files from one to the other each night or on demand (for about the next month, until this project is finished). So I'm thinking about using rsync.

My question is how do I set up the two Linode servers to communicate via private IP addresses securely? Both servers are SSH hardened, they use denyhosts and have a fairly restrictive iptables setup.

I know I need to first assign private IP addresses to each server, then configure static networking according to this guide.

What is next? What SSH or iptables settings are needed to allow these two servers to communicate?

What further info do I need to supply in this question? I'm looking for a basic step-by-step guide for how to do this.