SSH tunnel

SSH tunnelling in OpenWrt can be done by using the sshtunnel package. Its uci configuration is located in /etc/config/sshtunnel. This file is responsible for defining ssh servers and tunnels. Sshtunnel depends on openssh-client, because the ssh client included by default on OpenWrt (dropbear) doesn't support most of the needed features.

A typical sshtunnel config file contains at least one server specifying the connection to a ssh server and one or more tunnelL, tunnelR or tunnelD defining Local, Remote or Dynamic tunnels.

In most cases there will be only one server defined, but possibly several tunnels to this server.

A minimal server declaration may look like the example below.

config 'server' 'home'
	option 'user'       'jonh'
	option 'hostname'   'myhome.jonh.me'
	option 'port'       '22'

• home will identify this server on the tunnels sections
• jonh specifies the username on the remote machine
• myhome.jonh.me is the hostname of a machine running a openssh ssh server.

The possible options for server sections are listed in the table below.

A complete sshtunnel configuration contains at least one tunnelR, tunnelL, tunnelD or tunnelW sections, which will make use of a server.

A example for a tunnelR declaration is given below:

config tunnelR local_ssh
        option server         'home'
        option remoteaddress  '*'
        option remoteport     '2222'
        option localaddress   '127.0.0.1'
        option localport      '22'

• * means to accept a connection from any interface on the Server side

Specifying a remote bind_address will only succeed if the server's GatewayPorts option is enabled (see sshd_config(5))

• 2222 is the TCP port to bind on the Server side
• 127.0.0.1 is the OpenWrt side address to where the remote connection will be forwarded
• 22 is the OpenWrt side TCP port where to the remote connection will be forwarded

The equivalent ssh(1) command would be ssh -R *:2222:127.0.0.1:22 jonh@myhome.jonh.me

The possible options for tunnelR sections are listed in the table below:

For a tunnelL the declaration is similar:

config tunnelL server_http
        option server         'home'
        option remoteaddress  '127.0.0.1'
        option remoteport     '8080'
        option localaddress   '*'
        option localport      '80'

• 127.0.0.1 is the Server side address to where the connection will be forwarded
• 8080 is the Server side TCP port to where the local connection will be forwarded
• * means to accept a connection from any interface on the OpenWrt side
• 80 is the local TCP port to bind on the OpenWrt side

The equivalent ssh(1) command would be ssh -L *:80:127.0.0.1:8080 jonh@myhome.jonh.me

The possible options for tunnelL sections are listed in the table below:

A tunnelD declaration will create a SOCKS proxy accessible on the defined port:

config tunnelD proxy
        option server         'home'
        option localaddress   '*'
        option localport      '1080'

• * means to accept a connection from any interface on the OpenWrt side
• 1080 is the local TCP port to bind on the OpenWrt side

The equivalent ssh(1) command would be ssh -D *:1080 jonh@myhome.jonh.me

The possible options for tunnelD sections are listed in the table below:

A tunnelW declaration will TUN/TAP devices on client and server to establish a VPN tunnel between them.

config tunnelW vpn
	option server           'home'
	option vpntype		'point-to-point'
	option localdev		'any'
	option remotedev	'any'

The equivalent ssh(1) command would be ssh -o Tunnel=point-to-point -w any:any jonh@myhome.jonh.me

The possible options for tunnelW sections are listed in the table below:

See Arch Wiki VPN over SSH

• srv.us works with empty RemoteAddress or set to '*'. You can also set a custom domain as a number 1, 2 etc.
• localhost.run works with empty RemoteAddress or set to '*' but the generated domain will be rotated and changed on next restart. You need a custom domain (paid feature).
• remote.moe works only if a custom domain but this needs for some manual configuration.

See other options in the Awesome tunneling: SSH services

• Video: Setup SSH tunnel on router
• OpenWrt - Reverse SSH tunnel in Polish
• OpenWrt SSH tunnel
• LUCI app sshtunnel WIP
• howto: SOCKS Proxy SSH Tunnels on OpenWRT
• howto: OpenWrt SSH Tunneling
• sshtunnel SystemD port of the sshtunnel to other SystemD based Linux distros (Ubuntu, Debian etc).