Redundant OpenVPN connections with advanced Linux routing over an unreliable network
- by konrad
I am currently living in a country that blocks many websites and has unreliable network connections to the outside world. I have two OpenVPN endpoints (say: vpn1 and vpn2) on Linux servers that I use to circumvent the firewall. I have full access to these servers. This works quite well, except for the high package loss on my VPN connections. This packet loss varies between 1% and 30% depending on time and seems to have a low correlation, most of the time it seems random.
I am thinking about setting up a home router (also on Linux) that maintains OpenVPN connections to both endpoints and sends all packets twice, to both endpoints. vpn2 would send all packets from home to vpn1. Return trafic would be send both directly from vpn1 to home, and also through vpn2.
+------------+
| home |
+------------+
| |
| OpenVPN |
| links |
| |
~~~~~~~~~~~~~~~~~~ unreliable connection
| |
+----------+ +----------+
| vpn1 |---| vpn2 |
+----------+ +----------+
|
+------------+
| HTTP proxy |
+------------+
|
(internet)
For clarity: all packets between home and the HTTP proxy will be duplicated and sent over different paths, to increase the chances one of them will arrive. If both arrive, the first second one can be silently discarded.
Bandwidth usage is not an issue, both on the home side and endpoint side. vpn1 and vpn2 are close to each other (3ms ping) and have a reliable connection.
Any pointers on how this could be achieved using the advanced routing policies available in Linux?
