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@suma
Last active August 25, 2020 07:38
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Autossh init script(Ubuntu) for reverse ssh tunneling
#! /bin/sh
### BEGIN INIT INFO
# Provides: autosshd
# Required-Start: $remote_fs $syslog
# Required-Stop: $remote_fs $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: autosshd initscript
# Description: This file should be used to construct scripts to be
# placed in /etc/init.d.
### END INIT INFO
#
# autosshd This script starts and stops the autossh daemon
#
# chkconfig: 2345 95 15
# processname: autosshd
# description: autosshd is the autossh daemon.
# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh
# Define LSB log_* functions.
# Depend on lsb-base (>= 3.2-14) to ensure that this file is present
# and status_of_proc is working.
. /lib/lsb/init-functions
# Check that networking is up.
#[ ${NETWORKING} = "no" ] && exit 0
PATH=/sbin:/usr/sbin:/bin:/usr/bin
NAME=autossh
DAEMON=/usr/bin/$NAME
TUNNEL_HOST="your public ssh server"
TUNNEL_PORT=90022
DAEMON_ARGS=" -M 0 -f -nNT -i PATH_TO_YOUR/id_rsa -R $TUNNEL_PORT:localhost:22 $TUNNEL_HOST"
DESC="autossh for reverse ssh"
PIDFILE=/var/run/$NAME.pid
export AUTOSSH_PIDFILE=$PIDFILE
SCRIPTNAME=/etc/init.d/$NAME
#
# 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 --exec $DAEMON --test > /dev/null \
|| return 1
start-stop-daemon --start --quiet --exec $DAEMON -- \
$DAEMON_ARGS \
|| return 2
# Add code here, if necessary, that waits for the process to be ready
# to handle requests from services started subsequently which depend
# on this one. As a last resort, sleep for some time.
}
#
# 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
# Wait for children to finish too if this is a daemon that forks
# and if the daemon is only ever run from this initscript.
# If the above conditions are not satisfied then add some other code
# that waits for the process to drop all resources that could be
# needed by services started subsequently. A last resort is to
# sleep for some time.
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.
rm -f $PIDFILE
return "$RETVAL"
}
#
# Function that sends a SIGHUP to the daemon/service
#
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) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
esac
;;
status)
status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
;;
*)
echo "Usage: $SCRIPTNAME {start|stop|status|restart}" >&2
exit 3
;;
esac
:
Host remote_name
HostName 127.0.0.1 # or use your any hostname wrote to /etc/hosts in public ssh server
ProxyCommand ssh your_public_ssh_server nc localhost 90022
@xpander54
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are you having any trouble keeping the ssh tunnel open???

i cant seem to get a stable connection from raspberry pi to a vps

any ideas?

@tagsense
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hello
is it possible use a different ssh user than root? i tried multiple options:

  1. -l other_user
  2. --user argument for start-stop-daemon
  3. setting DAEMON_USER variable to other user

nothing seems to work.
any suggestions would be appreciated.
thanks in advance.

@mikemvk
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mikemvk commented Dec 27, 2015

Hello,

You can write username on TUNNEL_HOST variable.

TUNNEL_HOST="user@your_public_ssh_server"

@Clement-TS
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Clement-TS commented Aug 1, 2016

For some people experiencing this kindof errors:

  • Too many authentication failures (you have a lot of keys into your ~/.ssh, without a complete ~/.ssh/config)
  • The server unknown in your ~/.ssh/known_hosts

Add more options to your ssh command: -o IdentitiesOnly=yes -o StrictHostKeyChecking=no
This is especially true when it does not work as root, but sudo.

Also note that:

  • you do not use the autossh monitoring in this example. With monitoring enabled the stop command will not kill the "ssh" process
  • you should rather use the binary and not the wrapper of autossh : DAEMON=/usr/lib/autossh/autossh

@Clement-TS
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