The starting and stopping of a ProFTPD server is a straightforward process, once the means intended for such things are understood. Starting the server is easy. Stopping and/or restarting the server are the more complicated tasks. These can be accomplish either using signals or ftpshut, depending on your needs. Use of signals will fulfill most requirements; the ftpshut program is used for a specific way of shutting down a proftpd server.

Starting proftpd
init.d scripts vs command-line invocation standalone vs inetd

  /usr/local/sbin/proftpd [options]

 -h, --help
     Display proftpd usage
 -n, --nodaemon
     Disable background daemon mode and send all output to stderr)
 -q, --quiet
     Don't send output to stderr when running with -n or --nodaemon
 -d [level], --debug
     Set debugging level (0-9, 9 = most debugging)
 -D [definition], --define
     Set arbitrary IfDefine definition
 -c [config-file], --config
     Specify alternate configuration file
 -p [0|1], --persistent
     Enable/disable default persistent passwd support
 -l, --list
     List all compiled-in modules
 -t, --configtest
     Test the syntax of the specified config
 -v, --version
     Print version number and exit
 -vv, --version-status
     Print extended version information and exit

Signals
You will notice many proftpd processess running on your system, but you should not send signals to any of them except the parent, whose PID is in the PidFile. That is to say, you should not ever need to send signals to any process except the parent. There are two signals that you can send the parent: TERM and HUP, which will be described below.

To send a signal to the parent you should issue a command such as:

  kill -TERM `cat /usr/local/var/proftpd.pid`

  tail -f /usr/local/var/logs/proftpd.log

The TERM Signal (stop now)
Sending the TERM signal to the daemon parent process causes it to immediately attempt to kill off all of its children. It may take it several seconds to complete killing off its children. The daemon itself then exits. Any transfers in progress are terminated, and no further session requests are served.

Servers run out of inetd or xinetd (e.g. with a ServerType setting of inetd) will not need this signal, as their "parent" is the inetd or xinetd process.

The HUP Signal (restart now)
Sending the HUP signal to the daemon parent process causes it to re-read its configuration file(s), and re-opens any log files. Then it returns to handling new sessions. Any existing sessions will not be terminated.

Servers run out of inetd or xinetd will not need this signal; a new server process is started by the superserver process (e.g. inetd or xinetd) for every session request. This means that any changes to the configuration file will be visible to the next session after saving the changes to the file.

Note that if your configuration file has errors in it when you issue a restart then your parent will not restart, it will exit with an error. To avoid this, perform a syntax check of the file before sending the signal:

  proftpd -t -d5

Example init.d script

  #!/bin/sh

  # ProFTPD files
  FTPD_BIN=/usr/local/sbin/proftpd
  FTPD_CONF=/usr/local/etc/proftpd.conf
  PIDFILE=/var/run/proftpd.pid

  # If PIDFILE exists, does it point to a proftpd process?

  if [ -f $PIDFILE ]; then
   pid=`cat $PIDFILE`
  fi

  if [ ! -x $FTPD_BIN ]; then
    echo "$0: $FTPD_BIN: cannot execute"
    exit 1
  fi

  case $1 in

    start)
      if [ -n "$pid" ]; then
        echo "$0: proftpd [PID $pid] already running"
        exit
      fi

      if [ -r $FTPD_CONF ]; then
        echo "Starting proftpd..."

        $FTPD_BIN -c $FTPD_CONF

      else
        echo "$0: cannot start proftpd -- $FTPD_CONF missing"
      fi
      ;;

    stop)
      if [ -n "$pid" ]; then
        echo "Stopping proftpd..."
        kill -TERM $pid

      else
        echo "$0: proftpd not running"
        exit 1
      fi
      ;;

    restart)
      if [ -n "$pid" ]; then
        echo "Rehashing proftpd configuration"
        kill -HUP $pid

      else
        echo "$0: proftpd not running"
        exit 1
      fi
      ;;

    *)
      echo "usage: $0 {start|stop|restart}"
      exit 1
      ;;

  esac

  exit 0

The ftpshut program
The ftpshut program that comes as part of ProFTPD can also be used to shut down a proftpd server, in a sense. This program does not actually cause the server to stop completely, but rather places the server in an "administrative shutdown" state. This means that the server will still be handling session requests, but will deny incoming requests, telling clients to come back later. ftpshut allows the administrator to configure the server to start refusing connections at some future date, and also to disconnect existing sessions at some future date.

The situation in which this ability is most useful (a FAQ) is one where filesystem maintainenance or work needs to be done in the area from which the FTP server is serving files, but the server need not be shutdown. By placing the server in an "administrative shutdown" mode, clients are barred from their file while the adminstrative work is being done. Once completed, the server can be put back in normal operating mode by simply deleting the shutdown message file, described below.

The ftpshut program works by creating a file, usually /etc/shutmsg, for which the server checks periodically. This file will contain the time at which the server is to place itself in "administrative shutdown" mode, and times (if any) of refusing incoming connections, disconnecting existing connections. Unfortunately, many third-party administration tools use ftpshut to shut down proftpd servers, rather than using the method above. The problem with this approach is that, once restarted, the server will check for /etc/shutmsg, and will not accept incoming connections, leading to this FAQ; the third-party administration tool often forgets to delete that file once done.

Read ftpshut's man page for more detailed information on its usage.