OpenVPN through Tor

August 15, 2023

Someone was asking on Reddit how to pass traffic through Tor while exiting to the web from a non-Tor node. One way to do this would be to exit from any OpenVPN server which is not also a Tor exit node.

Principles:

• Specify a fixed bridge as the first hop for Tor, so that traffic can be sent to this IP address directly, without creating a routing loop between OpenVPN and Tor
• Use OpenVPN in TCP mode
• Specify Tor as a SOCKS proxy for OpenVPN
• Add a route to the bridge IP address over net_gateway (the pre-existing IP default gateway, read from the routing table)

Tor Browser:

obfs4 XX.XX.XX.XX:80 5EDA...9A08 cert=2upl...d0ew iat-mode=0

OpenVPN client configuration:

proto tcp
socks-proxy 127.0.0.1 9150
route XX.XX.XX.XX 255.255.255.255 net_gateway

Reference: https://tor.stackexchange.com/questions/22131/openvpn-over-tor.