How to trace a broken connection using bash?

Question

linux

To get started, I sequentially execute 2 commands in the terminal:
Connect to the VPN
$ ssh -D 9999 -N vpn &
And run the script where ports are forwarded to the VPN
$ ./proxy.sh
And now the process ./proxy.shhangs, and I work in the next tab of the terminal.
But periodically there is a disconnection and the process ./proxy.shstops.
Can I somehow track this moment and display, for example, Notification or somehow notify?
Script content ./proxy.sh:

#!/bin/bash

ssh \
  -L 9080:loc0.domain.com:80 \
  -L 9081:loc1.domain.com:80 \
  -L 9082:loc2.domain.com:80 \
  -N vpn

Googled the option -o "ServerAliveInterval 60". Apparently this is what you need?

Answer 1

And it’s trite to add output to the screen in proxy.sh

#!/bin/bash

ssh \
  -L 9080:loc0.domain.com:80 \
  -L 9081:loc1.domain.com:80 \
  -L 9082:loc2.domain.com:80 \
  -N vpn
echo "************ Proxy has been terminated ********"

And run it in the same tab where you work?
You can also add a 07 character to make it buzz.
You can put the launch of the proxy in an eternal while until you interrupt it yourself.
See what is more convenient.