OpenSSH ssh configuration example for Ubuntu 20.04 LTS (Focal Fossa)

Get the default configuration file ssh for OpenSSH, optimized for Ubuntu 20.04 LTS (Focal Fossa). This example configuration ensures optimal compatibility and performance for OpenSSH, making it easy to set up and adjust to meet your needs.

Find and download the configuration file here: /etc/init.d/ssh.

For more configurations and setup guides, visit our related files section to further customize your system.

    #! /bin/sh

### BEGIN INIT INFO
# Provides:		sshd
# Required-Start:	$remote_fs $syslog
# Required-Stop:	$remote_fs $syslog
# Default-Start:	2 3 4 5
# Default-Stop:		
# Short-Description:	OpenBSD Secure Shell server
### END INIT INFO

set -e

# /etc/init.d/ssh: start and stop the OpenBSD "secure shell(tm)" daemon

test -x /usr/sbin/sshd || exit 0
( /usr/sbin/sshd -\? 2>&1 | grep -q OpenSSH ) 2>/dev/null || exit 0

umask 022

if test -f /etc/default/ssh; then
    . /etc/default/ssh
fi

. /lib/lsb/init-functions

if [ -n "$2" ]; then
    SSHD_OPTS="$SSHD_OPTS $2"
fi

# Are we running from init?
run_by_init() {
    ([ "$previous" ] && [ "$runlevel" ]) || [ "$runlevel" = S ]
}

check_for_no_start() {
    # forget it if we're trying to start, and /etc/ssh/sshd_not_to_be_run exists
    if [ -e /etc/ssh/sshd_not_to_be_run ]; then 
	if [ "$1" = log_end_msg ]; then
	    log_end_msg 0 || true
	fi
	if ! run_by_init; then
	    log_action_msg "OpenBSD Secure Shell server not in use (/etc/ssh/sshd_not_to_be_run)" || true
	fi
	exit 0
    fi
}

check_dev_null() {
    if [ ! -c /dev/null ]; then
	if [ "$1" = log_end_msg ]; then
	    log_end_msg 1 || true
	fi
	if ! run_by_init; then
	    log_action_msg "/dev/null is not a character device!" || true
	fi
	exit 1
    fi
}

check_privsep_dir() {
    # Create the PrivSep empty dir if necessary
    if [ ! -d /run/sshd ]; then
	mkdir /run/sshd
	chmod 0755 /run/sshd
    fi
}

check_config() {
    if [ ! -e /etc/ssh/sshd_not_to_be_run ]; then
	/usr/sbin/sshd $SSHD_OPTS -t || exit 1
    fi
}

export PATH="${PATH:+$PATH:}/usr/sbin:/sbin"

case "$1" in
  start)
	check_privsep_dir
	check_for_no_start
	check_dev_null
	log_daemon_msg "Starting OpenBSD Secure Shell server" "sshd" || true
	if start-stop-daemon --start --quiet --oknodo --chuid 0:0 --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
	    log_end_msg 0 || true
	else
	    log_end_msg 1 || true
	fi
	;;
  stop)
	log_daemon_msg "Stopping OpenBSD Secure Shell server" "sshd" || true
	if start-stop-daemon --stop --quiet --oknodo --pidfile /run/sshd.pid --exec /usr/sbin/sshd; then
	    log_end_msg 0 || true
	else
	    log_end_msg 1 || true
	fi
	;;

  reload|force-reload)
	check_for_no_start
	check_config
	log_daemon_msg "Reloading OpenBSD Secure Shell server's configuration" "sshd" || true
	if start-stop-daemon --stop --signal 1 --quiet --oknodo --pidfile /run/sshd.pid --exec /usr/sbin/sshd; then
	    log_end_msg 0 || true
	else
	    log_end_msg 1 || true
	fi
	;;

  restart)
	check_privsep_dir
	check_config
	log_daemon_msg "Restarting OpenBSD Secure Shell server" "sshd" || true
	start-stop-daemon --stop --quiet --oknodo --retry 30 --pidfile /run/sshd.pid --exec /usr/sbin/sshd
	check_for_no_start log_end_msg
	check_dev_null log_end_msg
	if start-stop-daemon --start --quiet --oknodo --chuid 0:0 --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
	    log_end_msg 0 || true
	else
	    log_end_msg 1 || true
	fi
	;;

  try-restart)
	check_privsep_dir
	check_config
	log_daemon_msg "Restarting OpenBSD Secure Shell server" "sshd" || true
	RET=0
	start-stop-daemon --stop --quiet --retry 30 --pidfile /run/sshd.pid --exec /usr/sbin/sshd || RET="$?"
	case $RET in
	    0)
		# old daemon stopped
		check_for_no_start log_end_msg
		check_dev_null log_end_msg
		if start-stop-daemon --start --quiet --oknodo --chuid 0:0 --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
		    log_end_msg 0 || true
		else
		    log_end_msg 1 || true
		fi
		;;
	    1)
		# daemon not running
		log_progress_msg "(not running)" || true
		log_end_msg 0 || true
		;;
	    *)
		# failed to stop
		log_progress_msg "(failed to stop)" || true
		log_end_msg 1 || true
		;;
	esac
	;;

  status)
	status_of_proc -p /run/sshd.pid /usr/sbin/sshd sshd && exit 0 || exit $?
	;;

  *)
	log_action_msg "Usage: /etc/init.d/ssh {start|stop|reload|force-reload|restart|try-restart|status}" || true
	exit 1
esac

exit 0

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