wangmxf/autossh-tunnel

Setup and keep alive ssh tunnels to remote sites using autossh, screen

autossh-tunnel

Setup and keep alive ssh tunnels to remote sites using autossh, screen.

Requirements

• autossh
• screen

How it works

1. Sites to tunnel to are configured in ~/.ssh/config: Host declarations that start with 'autossh-' in the name are detected as candidates for tunnel sites. Example:

    Host autossh-HOSTNAME
    Hostname HOSTNAME
    User USER
    RemoteForward 8022 localhost:22
    IdentityFile ~/.ssh/autossh-id_rsa
   

2. ssh-keygen.sh: helper script to generate an SSH key without passphrase. Note: for added security, the public key is configured with the following options:

    command="/bin/false",no-agent-forwarding,no-X11-forwarding,no-pty
   

3. ssh-copy-id.sh: helper script to install SSH key in ~/.ssh/authorized_keys on each of the detected tunnel sites

4. setup.sh:

   Print the details of the detected setup:

   • SSH key that will be used with autossh
   • Detected tunnel sites in ~/.ssh/config
   • Confirmed tunnel sites (accepting the SSH key)

   Print the steps to complete the configuration.

   Print tips how to test the configuration.

5. autossh.sh: run autossh for each detected site in an independent screen session, unless already running

6. Add to crontab a line like this to periodically run autossh.sh:

    0 * * * * AUTOSSH_PORT=0 $PWD/autossh.sh
   

How to install

Simply run ./setup.sh and follow the steps. This script does not do anything. It only tells you the configuration it detected and gives you the steps you need to follow to complete the configuration.

How to uninstall

• Remove any cron jobs running autossh.sh
• ./stop.sh to stop any running autossh and screen instances
• Login to each tunnel site and manually remove the script's SSH key from ~/.ssh/authorized_keys