check-ssh-vpn.sh

This script checks whether the tunnel to a remote location is alife by checking whether port 22 can be accessed on it's private an public ip.

Usage:

check-ssh-vpn.sh <tun device> <public ip> <private ip>

Parameters:

• tun device: tunnel device to use and restart if necessary
• public ip: public ip of the server at our remote locations
• private ip: private ip of the server at our remote locations

Side note: We use this inside a crontab on our router to make sure the vpn connection between two of our locations stays active.

# VPN-tunnel check/create
* * * * * <path to check-ssh-vpn.sh> <tunnel device> <public ip> <private ip>

This maps the 'remote ip' to the 'local ip' of the remote .

Note: The tunnel device contains most of the configuration and is specified inside /etc/network/interfaces. see: https://x.graph-it.com/mediawiki/index.php/VPN_tunnel for details