Project

General

Profile

Support #829

Updated by Daniel Curtis over 8 years ago

This is a guide for setting up a persistent reverse SSH tunnel using AutoSSH on Arch Linux.  

 Once completed, the service that will autostart at boot will open port 5000 on the remote SSH connection that will allow SSH connections back to the originating host. 

 h2. Prepare the Environment 

 * Switch to the root user: 
 <pre> 
 sudo -s 
 </pre> 

 * Make sure the system is up to date: 
 <pre> 
 pacman -Syu 
 </pre> 

 * Generate a root ssh keypair: 
 <pre> 
 ssh-keygen -t ed25519 
 </pre> 

 * Copy the ssh public key to the remote host: 
 <pre> 
 ssh-copy-id bob@ssh.example.com 
 </pre> 

 h2. AutoSSH 

 * Install autossh: 
 <pre> 
 pacman -S autossh 
 </pre> 

 h3. Host Config 

 * Create a .ssh config file: 
 <pre> 
 nano ~/.ssh/config 
 </pre> 
 #* And add the following: 
 <pre> 
 Host remote-tunnel-home 
    HostName        ssh.example.com 
    User            bob 
    Port            7022 
    IdentityFile    ~/.ssh/id_ed25519 
    RemoteForward    5000 localhost:22 
    ServerAliveInterval 30 
    ServerAliveCountMax 3 
 </pre> 

 h3. Systemd Service 

 * Create the autossh reverse tunnel service file: 
 <pre> 
 nano /etc/systemd/system/autossh-reverse-tunnel-home.service 
 </pre> 
 #* And add the following: 
 <pre> 
 [Unit] 
 Description=AutoSSH tunnel to remote SSH host on local port 5000 
 After=network.target 

 [Service] 
 Environment="AUTOSSH_GATETIME=0" 
 ExecStart=/usr/bin/autossh -M 0 -f -T -N remote-tunnel-home 

 [Install] 
 WantedBy=multi-user.target 
 </pre> 

 * Refresh the systemd units: 
 <pre> 
 systemctl daemon-reload 
 </pre> 

 * Start *Start and enable the service at boot: 
 <pre> 
 systemctl start autossh-reverse-tunnel-home.service 
 systemctl enable autossh-reverse-tunnel-home.service 
 </pre> 

 h2. Resources 

 * https://raymii.org/s/tutorials/Autossh_persistent_tunnels.html 
 * https://www.everythingcli.org/ssh-tunnelling-for-fun-and-profit-autossh/ 
 * https://blog.sleeplessbeastie.eu/2014/12/23/how-to-create-persistent-reverse-ssh-tunnel/ 
 * https://wiki.archlinux.org/index.php/Secure_Shell#Run_autossh_automatically_at_boot_via_systemd

Back