Running without systemd

The NoPorts daemon doesn't have to be run by systemd

Once NoPorts is installed with a /etc/noports/sshnpd.yaml config and an atKeys file all that's needed to start the daemon is to run sshnpd .

But... without systemd there's nothing to restart sshnpd if it exits, and there's nothing capturing logs (and compressing, rotating and pruning them).

At the most basic level a simple script will restart the daemon if it fails:

#!/bin/bash
BACKOFF_INTERVAL=10
while true; do
  sshnpd
  sleep "$BACKOFF_INTERVAL"
done

Whatever runs sshnpd should be some kind of background task (so it doesn't exit when the session launching it is disconnected). For example redirect logs and run in background with:

nohup sshnpd > sshnpd.log 2> sshnpd.err < /dev/null &

A similar effect can be achieved by running sshnpd inside a terminal multiplexer such as GNU Screen or Tmux.