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. 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). Now you should be able to connect to the SSH service on the local machine from the remote server using port 9000, while autossh is managing the SSH tunnel.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. Su -s /bin/sh sshtunnel -c "autossh -f -i ~/.ssh/tunnel_key_a remote-server -N -R 9000:localhost:22" Contrary to how SSH works, where you establish a secure connection with a remote system and can receive and send data, in reverse SSH, the remote system connects with your local system. # In order to enable or disable this script just change the execution Reverse SSH tunneling or remote port forwarding helps you connect to a remote (and private) network without needing a public gateway. # Make sure that the script will "exit 0" on success or any other # This script is executed at the end of each multiuser runlevel. $ sudo sed -i -e '$i # create sshtunnel\nsu -s /bin/sh sshtunnel -c "autossh -f -i ~/.ssh/tunnel_key_a remote-server -N -R 9000:localhost:22"\n' /etc/rc.local $ sudo su -s /bin/sh sshtunnel -c "autossh -v -i ~/.ssh/tunnel_a remote-server -N -R 9000:localhost:22"ĭebug1: Reading configuration data /etc/ssh/ssh_configĪuthenticated to remote-server (:22).ĭebug1: remote forward success for: listen 60654, connect 127.0.0.1:60655ĭebug1: remote forward success for: listen 9000, connect localhost:22ĭebug1: All remote forwarding requests processedĪdd autossh command to the /etc/rc.local script to start a ssh tunnel at boot. Use the following command on the local machine to test the reverse SSH tunnel to the remote server. $ ssh-keyscan -H -t rsa remote-server | sudo su -s /bin/sh sshtunnel -c "tee > ~/.ssh/known_hosts" Fourth step #Īdd remote server to the known servers pool on the local machine. Now you can remove the uploaded public key. Now, when I try to access the machine from aws, I got the following: ssh ronlocalhost -P 19999 Permission denied (publickey). $ echo 'no-agent-forwarding,no-user-rc,no-X11-forwarding,no-pty' $(cat tunnel_key_a.pub) | sudo su -s /bin/bash sshtunnel -c "tee > ~/.ssh/authorized_keys" Im using autossh -M 20000 -fN -R 19999:localhost:22 -i mycert.pem email protected to establish a reverse tunnel to my aws machine. 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. $ sudo su -s /bin/sh sshtunnel -c "mkdir ~/.ssh"Īdd uploaded public key to the pool of keys authorized for authentication. Upload ~/.ssh/tunnel_key_a.pub file to the remote server and perform the following operations while still being connected to it.Ĭreate a missing. Sshtunnel$ ssh-keygen -t rsa -b 2048 -q -N "" -f ~/.ssh/tunnel_key_a Switch to the sshtunnel user and create SSH key pair. $ sudo useradd -s /usr/sbin/nologin -m sshtunnel Second step #Ĭreate sshtunnel user on the local machine. It is crucial to disable shell access, but create a home directory to store SSH configuration ( known hosts and authorized keys). The easiest way to do this is to use autossh utility to create a secure and persistent reverse SSH tunnel to the publicly available server.Ĭonnect to the remote server and create sshtunnel user. Sometimes I want to access a private server at home from a different network while being on the go.
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