OpenSSH sshd configuration example for CentOS Linux 7

Get the default configuration file sshd for OpenSSH, optimized for CentOS Linux 7. 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/rc.d/init.d/sshd.

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

    #!/bin/bash
#
# sshd		Start up the OpenSSH server daemon
#
# chkconfig: 2345 55 25
# description: SSH is a protocol for secure remote shell access. \
#              This service starts up the OpenSSH server daemon.
#
# processname: sshd
# config: /etc/ssh/ssh_host_key
# config: /etc/ssh/ssh_host_key.pub
# config: /etc/ssh/ssh_random_seed
# config: /etc/ssh/sshd_config
# pidfile: /var/run/sshd.pid

### BEGIN INIT INFO
# Provides: sshd
# Required-Start: $local_fs $network $syslog
# Required-Stop: $local_fs $syslog
# Should-Start: $syslog
# Should-Stop: $network $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start up the OpenSSH server daemon
# Description:       SSH is a protocol for secure remote shell access.
#		     This service starts up the OpenSSH server daemon.
### END INIT INFO

# source function library
. /etc/rc.d/init.d/functions

# pull in sysconfig settings
[ -f /etc/sysconfig/sshd ] && . /etc/sysconfig/sshd

RETVAL=0
prog="sshd"
lockfile=/var/lock/subsys/$prog

# Some functions to make the below more readable
SSHD=/usr/sbin/sshd
XPID_FILE=/var/run/sshd.pid
PID_FILE=/var/run/sshd-s.pid

runlevel=$(set -- $(runlevel); eval "echo \$$#" )

do_restart_sanity_check()
{
	$SSHD -t
	RETVAL=$?
	if [ $RETVAL -ne  0 ]; then
		failure $"Configuration file or keys are invalid"
		echo
	fi
}

start()
{
	[ -x $SSHD ] || exit 5
	[ -f /etc/ssh/sshd_config ] || exit 6
	# Create keys if necessary
	/usr/sbin/sshd-keygen

	echo -n $"Starting $prog: "
	$SSHD $OPTIONS && success || failure
	RETVAL=$?
	[ $RETVAL -eq 0 ] && touch $lockfile
	[ $RETVAL -eq 0 ] && cp -f $XPID_FILE $PID_FILE
	echo
	return $RETVAL
}

stop()
{

	echo -n $"Stopping $prog: "
	if [ ! -f "$PID_FILE" ]; then
		# not running; per LSB standards this is "ok"
		action $"Stopping $prog: " /bin/true
		return 0
	fi
	PID=`cat "$PID_FILE"`
	if [ -n "$PID" ]; then
		/bin/kill "$PID" >/dev/null 2>&1
		RETVAL=$?
		if [ $RETVAL -eq 0 ]; then
			RETVAL=1
			action $"Stopping $prog: " /bin/false
		else
			action $"Stopping $prog: " /bin/true
		fi
	else
		 # failed to read pidfile
		action $"Stopping $prog: " /bin/false
		RETVAL=4
	fi
	# if we are in halt or reboot runlevel kill all running sessions
	# so the TCP connections are closed cleanly
	if [ "x$runlevel" = x0 -o "x$runlevel" = x6 ] ; then
	    trap '' TERM
	    killall $prog 2>/dev/null
	    trap TERM
	fi
	[ $RETVAL -eq 0 ] && rm -f $lockfile
	rm -f "$PID_FILE"
        return $RETVAL
}

reload()
{
	echo -n $"Reloading $prog: "
	if [ -n "`pidfileofproc $SSHD`" ] ; then
	    killproc $SSHD -HUP
	else
	    failure $"Reloading $prog"
	fi
	RETVAL=$?
	echo
}

restart() {
	stop
	start
}

force_reload() {
	restart
}

rh_status() {
	status -p $PID_FILE openssh-daemon
}

rh_status_q() {
	rh_status >/dev/null 2>&1
}

case "$1" in
	start)
		rh_status_q && exit 0
		start
		;;
	stop)
		if ! rh_status_q; then
			rm -f $lockfile
			exit 0
		fi
		stop
		;;
	restart)
		restart
		;;
	reload)
		rh_status_q || exit 7
		reload
		;;
	force-reload)
		force_reload
		;;
	condrestart|try-restart)
		rh_status_q || exit 0
		if [ -f $lockfile ] ; then
			do_restart_sanity_check
			if [ $RETVAL -eq 0 ] ; then
				stop
				# avoid race
				sleep 3
				start
			else
				RETVAL=6
			fi
		fi
		;;
	status)
		rh_status
		RETVAL=$?
		if [ $RETVAL -eq 3 -a -f $lockfile ] ; then
			RETVAL=2
		fi
		;;
	*)
		echo $"Usage: $0 {start|stop|restart|reload|force-reload|condrestart|try-restart|status}"
		RETVAL=2
esac
exit $RETVAL

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