+++
date = "2018-01-08T21:37:32+00:00"
publishdate = "2023-12-29T07:08:55+00:00"
title = "SSH Port Fowarding Tunnels"
slug = "ssh-port-forwarding"
author = "Thedro"
tags = ["ssh","linux"]
type = "posts"
summary =  "The other day I needed to set up a Syncthing instance on a remotely networked server that had no graphical display."
draft =  ""
syntax =  "1"
toc =  ""
updated =  ""
+++

{{< image source="/images/ssh-port-forwarding.png" >}} {{< /image >}}

The other day I needed to set up a
[Syncthing](https://github.com/syncthing/syncthing#readme) instance on a
remotely networked server that had no graphical display. I didn't want to set it
up using the command line tools and I definitely did not want to install a
graphical environment on the server to access the web `GUI`.

There is another computer with a graphical display on the local network. The
only problem is that a standard `syncthing` installation does not have its port
(`8384`) exposed to computers on the local network. We would be unable to access
the web server.

This means that one would need to expose that port either by configuring
`syncthing` directly or by opening up the respective port. That direction is
more involved. There is a great solution to this problem and it's called `SSH`
port forwarding. The solution comes down to this single command.

```shell
ssh -v -NL 12345:127.0.0.1:8384 machine.remote
```

The above command states that it will forward or bind port `8384` of `127.0.0.1`
(`syncthing`) from `machine.remote` to `localhost's` port `12345` (computer with
the graphical display) such that the user on `localhost` can access
`machine.remote's` port `8384` as if it was on port `12345`. The `-N` flag
prevents the `SSH` command from executing on the remote so that it is forced to
run as a foreground process at the command line.