Actualy is just exports TMOUT option per login

I think this feature must then be modified with:

1. Add TMOUT also for the root-user (I assume this would fix the case of when vyos user have runned "sudo bash" and left the screen/console?).

2. Add following to /etc/ssh/sshd_config

ClientAliveInterval <seconds>
ClientAliveCountMax 1

Ref1: https://ostechnix.com/auto-logout-inactive-users-period-time-linux/

Ref2: https://linuxhandbook.com/auto-logout-linux/

My proposal after some testing:

1. Delete file /etc/profile.d/autologout.sh

2. Add these lines to the bottom of /etc/bash.bashrc

TMOUT=<seconds>
readonly TMOUT
export TMOUT

This way the timeout will occur for both regular users AND root user.

Testing:

Verified with the bash.bashrc changes (note the double timeout when user runs "sudo bash" because first the timeout triggers for root and then for the regular user which means if you use for example timeout 600 seconds when the user is logged as regular user who have elevated to root through "sudo bash" it will take 2x600 seconds before the user is kicked out of inactivity):

Regular user:

vyos@vyos:~$ timed out waiting for input: auto-logout
Connection to 192.168.56.2 closed.

Regular user who have elevated through "sudo bash":

root@vyos:/home/vyos# 
timed out waiting for input: auto-logout
vyos@vyos:~$ timed out waiting for input: auto-logout
Connection to 192.168.56.2 closed.

Note:

I did try these lines by altering /usr/share/vyos/templates/ssh/sshd_config.j2 (and rebooting system and verifying that it picked up the values in /run/sshd/sshd_config):

ClientAliveInterval <seconds>
ClientAliveCountMax 1

but it failed to have any effect by configuring these - perhaps somebody else have a better luck?

The idea would be to get rid of the double timeout an elevated root user gets.

There is also an inactivity timer in systemd-logind, but this will log you out even while running e.g. htop and just watching - I wonder if that's the preferred way :/