Starting SNORT on reboot

In order that snort start automatically on rebooting Ubuntu copy paste the script on to a text file and save it as snort in the path /etc/init.d/

I have changed the font color where I have made my customization.
 
Source from snort's blog and Bullet-bala.blogspot.com made few changes & customization :-)

#! /bin/sh
### BEGIN INIT INFO
# Provides:          Snort
# Required-Start:    $local_fs $remote_fs $syslog $network mysql
# Required-Stop:     $local_fs $remote_fs $syslog $network mysql
# Default-Start:     2 3 4 5
# Default-Stop:      S 0 1 6
# Short-Description: Init script to start the Snort daemon
# Description:       Provides Snort service on startup and terminates
#                    on shutdown. Snort is an IDS or IPS. This script
#                    assumes that snort is installed in /usr/sbin and
#                    that it's main snort.conf file is in /etc/snort.
#                    The service will be started as a daemon, listening
#                    on eth0 and will also start quietly. If you require
#                    something other than this, you will have to edit
#                    the script accordingly.
#                    USE AT YOUR OWN RISK, YMMV. THIS SCRIPT COMES WITH
#                    ABSOLUTELY NO WARRANTY WHATSOEVER.
# License:           GPLv2 see http://www.gnu.org/licenses/gpl-2.0.txt
### END INIT INFO

# Author: Nigel Houghton

PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/sbin:/usr/local/bin
export LD_LIBRARY_PATH=/usr/local/lib
DESC="Snort service for IDS or IPS"
NAME=snort
CONFIG="/store/snort/etc/snort.conf"
INTERFACE="eth1"
DAEMON=/usr/local/bin/$NAME
SNORTUser="suser"
#The -q is for quite mode and -D is for deamon refer http://projects.cs.luc.edu/comp412/dredd/docs/software/man-snort
DAEMON_ARGS="-c $CONFIG -i $INTERFACE -u $SNORTUser -qD"
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/$NAME

# Exit if the package is not installed
[ -x "$DAEMON" ] || exit 1

# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Load the VERBOSE setting and other rcS variables
[ -f /etc/default/rcS ] && . /etc/default/rcS

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

#
# Function that starts the daemon/service
#
do_start()
{
 # Return
 #   0 if daemon has been started
 #   1 if daemon was already running
 #   2 if daemon could not be started
 start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --test > /dev/null \
  || return 1
 start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON -- \
  $DAEMON_ARGS \
  || return 2
}

#
# Function that stops the daemon/service
#
do_stop()
{
 # Return
 #   0 if daemon has been stopped
 #   1 if daemon was already stopped
 #   2 if daemon could not be stopped
 #   other if a failure occurred
   start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE --name $NAME
 RETVAL="$?"
 [ "$RETVAL" = 2 ] && return 2
 start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON
 [ "$?" = 2 ] && return 2
 # Many daemons don't delete their pidfiles when they exit.
 if [ -f "$PIDFILE" ]; then
    rm -f $PIDFILE
   fi
 return "$RETVAL"
}

#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
 start-stop-daemon --stop --signal 1 --quiet --pidfile $PIDFILE --name $NAME
 return 0
}

case "$1" in
  start)
 [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
 do_start
 case "$?" in
  0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
  2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
 esac
 ;;
  stop)
 [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
 do_stop
 case "$?" in
  0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
  2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
 esac
 ;;
  restart|force-reload)
 log_daemon_msg "Restarting $DESC" "$NAME"
 do_stop
 case "$?" in
   0|1)
  do_start
  case "$?" in
   0) log_end_msg 0 ;;
   1) log_end_msg 1 ;; # Old process is still running
   *) log_end_msg 1 ;; # Failed to start
  esac
  ;;
   *)
    # Failed to stop
  log_end_msg 1
  ;;
 esac
 ;;
  *)
 echo "Usage: $SCRIPTNAME {start|stop|restart|force-reload}" >&2
 exit 3
 ;;
esac

:
You need to paste upto the semicolon shown above. Just in case this does not show well on blogger here is a pastebin link http://pastebin.com/Ew9VBGBK. Once this is done we need to use update.rc.d script in Ubuntu.

A good article of how to use that is given here http://www.debuntu.org/how-to-manage-services-with-update-rc.d. Don't worry I will not make you read that to understand the next command.

Here I have asked Ubuntu to start my snort script with 99th priority (i.e start as late as possible) on runlevels 2 3 4 and 5 and to kill it with 99th priority (i.e immediately )when ubuntu hit runlevel 0 1 and 6.

  At the end you can confirm if snort is running with the command


bala@Bodhidarmar:~$ ps aux | grep snort
aravind    774  0.8 28.0 657556 211748 ?       Ssl  03:32   0:00 /usr/local/bin/snort -c /store/snort/etc/snort.conf -i eth1 -u suser -qD
bala       796  0.0  0.1   3324   784 pts/1    S+   03:32   0:00 grep --color=auto snort
bala@Bodhidarmar:~$