What is the recommended way to permanently connect two remote linux based environments together?

Solution 1:

I would recommend linking them together with OpenVPN. OpenVPN allows you to link networks together. You can find a very detailed walkthrough here. Everything is secure that way.

Solution 2:

I think OpenVPn may be your answer (see what TiZon said).

However just to complete the picture, serious ways of doing this would be:

• Site-to-site hardware firewall terminated VPN

The firewall in location A maintains a constant VPN to the firewall in location B, allowing servers behind either firewall to communicate as if they were on the same network.

• MPLS

Have a MPLS line terminated into your two locations, and send traffic into the telecom provider's MPLS cloud. To your network devices it will look like all your boxes are on the same layer 2 network, but in practise their communications will be encapulated into the MPLS network.