(With tap-mode VPN it's just a single kernel route combining both. If you're using tun-mode VPN, the server just needs a kernel route for your LAN subnet through tun0, and then an OpenVPN iroute for the same subnet through the home VPN client's address. When running a wget command from the VPS, it works and the ssh log relects that. So, I ran the reverse tunnel manually with the -vv tag. Note that autossh was previously often used for this (and nearly all existing online tutorials about reverse ssh tunnels use autossh) but autossh is redundant nowadays since modern openssh versions can monitor link health and exit if the link fails, and systemd can then be used to restart the ssh tunnel. This way you'll even be able to use UDP without any NAT-related problems, as long as you enable periodic ping in the client or otherwise maintain frequent traffic over the tunnel. Nov 15 23:59:52 nextcloud autossh7430: starting ssh (count 1) Nov 15 23:59:52 nextcloud autossh7430: ssh child pid is 7459. (Yes, the OpenVPN server will forward data between your 'home' and 'roaming' clients with no problems.) To start using it you need a config like this: LocalPort TargetHost TargetPort SshHost SshUsername SshKeyPath 18080 80 User D:\secure\path\to\privatekey.ppk. ![]() Yours: IPv4 | TCP | SSH | OpenVPN | IPv4 | TCP | applicationĪs you already have a VPS, put the OpenVPN server there – and have your home system connect "out" to the VPS instead of the reverse. Vpn: IPv4 | UDP | OpenVPN | IPv4 | TCP | application Learn more about bidirectional Unicode characters. that makes it easier to define a reverse ssh port forwarding tunnel from the target server to the jump host. To review, open the file in an editor that reveals hidden Unicode characters. rvice This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. Of course, one layer is unavoidable for a VPN, but doubling it might be noticeable. AutoSSH reverse tunnel service config for systemd Raw. This might not work well.įinally, throughput will be reduced by the tunnel overhead alone (SSH and OpenVPN packet headers eating into the available baseline 1500-byte MTU). ![]() You also have three layers of nested TCP flow control (your regular traffic, inside the OpenVPN layer, inside the SSH layer). You’d have traditionally used ssh to setup a tunnel for port-forwarding like below ssh -L -gNC 15672:targetsystemiporhostname:15672 bastionhost Your autossh based equivalent to have an ssh. (Even then, the SSH software rarely provides top performance.) If I then issue a sudo pkill -signal HUP sshd on the server and then attempt to reach the clients that are configured to run autossh. When I issue netstat grep ssh on the remote server, I see multiple 'ESTABLISHED' ssh connections. You have two layers of encryption (SSH and OpenVPN), which might reduce performance – higher CPU usage and lower throughput, especially if one of your three involved devices doesn't have hardware crypto acceleration. If I reboot the clients, I will get a connection refused message when attempting to reconnect from my local PC. ![]() Worse, when during an existing tunnel connection, the local Server is shut down (either with a clean TCP shutdown, or even with a TCP-RESET) this is NOT forwarded back to the external client, and from this Client's perspective, the connection still exists.What are the security/performance implications of such a solution? In particular the last bit is important as I need to go through some firewalls / NATs to access some of the machines. ![]() Still, a TCP connection is established on that external port. Which should cause a local RESET from that PC. My problem is that the SSH accepts incoming connections on the external ports, even when there is no end-point That is, the local Server is not running at all (but the PC is). I am using ssh reverse tunnels (using AutoSSH) to allow incoming connections on certain ports on my Internet server, to be tunneled to Local Servers on my house LAN.
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