OpenWrt SSH tunnel

OpenWrt SSH tunnel.md

Short how-to for creating a reverse ssh tunnel to a remote server. Useful for breaking NATted connection for example.

1. At OpenWrt:

opkg update
opkg install sshtunnel

2. At remote server: create client ssh keys

ssh-keygen -b 2048 -t rsa

Move the resulting private key to OpenWrt /root/.ssh/id_rsa, and assign chmod 600.

3. At remote server: Authorize OpenWrt client at remote server (authorized_keys)

4. At OpenWrt: Store remote host public key as known host

ssh MYUSER@REMOTEHOST
# accept yes, and press ctrl + c

5. At OpenWrt: Enable service (Start on bootup)

/etc/init.d/sshtunnel enable

6. At OpenWrt: Start service

/etc/init.d/sshtunnel start

7. At OpenWrt: configure sshtunnel

See https://wiki.openwrt.org/doc/uci/sshtunnel for more information

Example configuration

config server myremote
	option user	myuser
	option hostname	remotehost
	option IdentityFile	/root/.ssh/id_rsa
	option retrydelay	5
	option ServerAliveInterval	30
	option ServerAliveCountMax	3
	option LogLevel		DEBUG1

config tunnelR sshtunnel
	option server	myremote
	option remoteport	44423
	option remoteaddress	*
	option localport	22
	option localaddress	127.0.0.1

/etc/init.d/sshtunnel reload

In order to allow binding to all interfaces, server configuration might need changing, see this comment in stackoverflow.com on GatewayPorts setting.

Great article. But I have password authorization on an ssh server (Ubuntu). Is there any way to automate the connection using sshtunnel to my Ubuntu server by password?

@lavinkabul no, it's not possible. You need to setup the Public Key Auth. It's like a password that is stored in a file. But splitted into public key id_rsa.pub and a secret id_rsa.

The new wiki page about the sshtunnel is https://openwrt.org/docs/guide-user/services/ssh/sshtunnel
@samaaron I created a Luci app to configure the SSH tunnel openwrt/luci#6424
Could you please try it and give a feedback?

For Ubuntu and other desktop Linux I created the https://github.com/yurt-page/sshtunnel