This is a short recipe on how to setup Syncthing for syncing files between my Windows workstation and a Debian web server over internet. Syncing is done through a ssh tunnel, no need to expose any public ports to the internet.

Prerequisites

Putty bundle installed on the Windows workstation (this time we need plink.exe)

Syncthing setup on Debian server

Follow the instructions provided here
Just in case, here they are:

 # Add the release PGP keys:
 curl -s https://syncthing.net/release-key.txt | sudo apt-key add -

 # Add the "release" channel to your APT sources:
 echo "deb http://apt.syncthing.net/ syncthing release" | sudo tee /etc/apt/sources.list.d/syncthing.list

 # Update and install syncthing:
 sudo apt-get update
 sudo apt-get install syncthing

In case you need to edit any settings like ports you need to edit ~/.config/syncthing/config.xml

Create the file /etc/init.d/syncthing

 sudo touch /etc/init.d/syncthing
 sudo chmod 755 /etc/init.d/syncthing
 sudo chown root:root /etc/init.d/syncthing

With the following content:

 #!/bin/sh
 ### BEGIN INIT INFO
 # Provides: syncthing
 # Required-Start: $local_fs $remote_fs
 # Required-Stop: $local_fs $remote_fs
 # Should-Start: $network
 # Should-Stop: $network
 # Default-Start: 2 3 4 5
 # Default-Stop: 0 1 6
 # Short-Description: Multi-user daemonized version of syncthing.
 # Description: Starts the syncthing daemon for all registered users.
 ### END INIT INFO

 # Replace with users you want to run syncthing clients for
 syncthing_USERS="myusername"
 DAEMON=/usr/bin/syncthing

 startd() {
 for stuser in $syncthing_USERS; do
     HOMEDIR=$(getent passwd $stuser | awk -F: '{print $6}')
     if [ -f $config ]; then
     echo "Starting syncthiing for $stuser"
     start-stop-daemon -b -o -c $stuser -S -u $stuser -x $DAEMON
     else
     echo "Couldn't start syncthing for $stuser (no $config found)"
     fi
 done
 }

 stopd() {
 for stuser in $syncthing_USERS; do
     dbpid=$(pgrep -fu $stuser $DAEMON)
     if [ ! -z "$dbpid" ]; then
     echo "Stopping syncthing for $stuser"
     start-stop-daemon -o -c $stuser -K -u $stuser -x $DAEMON
     fi
 done
 }

 status() {
 for stuser in $syncthing_USERS; do
     dbpid=$(pgrep -fu $stuser $DAEMON)
     if [ -z "$dbpid" ]; then
     echo "syncthing for USER $stuser: not running."
     else
     echo "syncthing for USER $stuser: running (pid $dbpid)"
     fi
 done
 }

 case "$1" in
 start) startd
     ;;
 stop) stopd
     ;;
 restart|reload|force-reload) stopd && startd
     ;;
 status) status
     ;;
 *) echo "Usage: /etc/init.d/syncthing {start|stop|reload|force-reload|restart|status}"
     exit 1
 ;;
 esac

 exit 0

Don’t forget to set syncthing_USERS to the desired user for running syncthing.

Now run
```
 /etc/init.d/syncthing start
```
Which will start the daemon.

To make it autostart on bootup run

 sudo update-rc.d syncthing defaults
 sudo update-rc.d syncthing enable

Windows workstation setup

Download the Syncthing Core (CLI & Web UI) for Windows
Extract it to C:\Program Files\syncthing

Create “C:\Program Files\syncthing\SYNCNOW.bat” with the following content:

start syncthing.exe
start "" http://localhost:8385
"C:\Program Files (x86)\PuTTY\plink.exe" -L 22001:127.0.0.1:22000 -L 8385:127.0.0.1:8384 yoursshuser@your.debian.server.com

Two web pages should open http://localhost:8385/ and http://127.0.0.1:8384/
Proceed to adding both machines IDs so they can see each other. (Check Syncthing instructions for more info on basic setup)

That’s it. I prefer to run syncthing on the workstation manually only when I need to. So when file syncing is needed, SYNCNOW.bat should be ran manually and syncing should work. You can easily stop the process by simply closing all the opened cmd windowns.

Permissions clash

Someone asked what to do if syncthng is creating files and directories with a syncuser:syncgroup different from what apache is using and thus apache cannot access file/dirs created by sync user. One solution that comes to mind is the following:

Modify /etc/init.d/syncthing from

start-stop-daemon -b -o -c $stuser -S -u $stuser -x $DAEMON

start-stop-daemon -b -o -c $stuser -S -u $stuser -x $DAEMON --umask 002

In the windows workstation web ui set “Ignore Permissions” to true. This seems to be required to have newly-created files on linux-based server be writable by the group https://github.com/syncthing/syncthing/issues/1339
Run the following commands on server (presuming that /var/www/sync is the dir shared by apache and syncthing):
```
chown -R syncuser:www-data /var/www
chmod -R g+s /var/www
```

Now all new dirs and files should preserve www-data group and have rw-rw-r– permissions.

(If anyone knows a more better way, please let me know.)