Before running the ntopng.SlackBuild script, you will need to create
the 'ntop' user and group. The script won't run if these do not exist.

The suggested UID and GID is 212, but you can change this as needed:

  groupadd -g 212 ntop
  useradd -u 212 -g ntop -d /var/lib/ntopng -s /usr/bin/bash ntop

Edit the $INTERFACE variable in rc.ntopng with the name of the one
you want ntopng to listen on.

If you want to start ntopng on system bootup, include these lines in
your /etc/rc.d/rc.local:

  # Start ntopng
  if [ -x /etc/rc.d/rc.ntopng ]; then
    echo "Starting ntpong server..."
    /etc/rc.d/rc.ntopng start
  fi

*IMPORTANT*: the redis server must be started *before* ntopng so do
the same for rc.redis

To guarantee a clean shutdown of ntopng, include this in
/etc/rc.d/rc.local_shutdown:

  # Stop ntopng
  if [ -x /etc/rc.d/rc.ntopng ]; then
    echo "Stopping ntopng server..."
    /etc/rc.d/rc.ntopng stop
  fi

(and do the same for rc.redis accordingly)

Additionally, you'll have to set the rc script to be executable just
like any other Slackware rc script:

  chmod +x /etc/rc.d/rc.ntopng

After starting the ntop web interface will be reachable on port 3000.