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adds sshuttle

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waldek 2021-07-13 16:05:37 +02:00
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modules/qualifying/learning_ssh.md
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@ -323,11 +323,12 @@ Last login: Tue Jul 13 14:12:18 2021 from 172.30.40.99
We've done quite a bit of SFTP before so we won't go into detail here but if you forgot, go have a look at the networking exercises in the resources directory. We've done quite a bit of SFTP before so we won't go into detail here but if you forgot, go have a look at the networking exercises in the resources directory.
I'm mentioning it because it's crucial to remember it's existence in order to understand the next topic, sshfs. I'm mentioning it because it's crucial to remember it's existence in order to understand the next topic, sshfs.
If it's all a bit vague I urge you to read the `man sftp-server`.
## SSHFS ## SSHFS
Thanks to the sftp subsystem of ssh we can use it to copy files form one system to an other. Thanks to the sftp subsystem of ssh we can use it to copy files form one system to an other.
Some clever guy's used it to build [sshfs]() which mounts a remote folder into our system so we can use it like a network share. Some clever guy's used it to build [sshfs](https://wiki.archlinux.org/title/SSHFS) which mounts a remote folder into our system so we can use it like a network share.
It's a poor mans NFS that can be a true lifesaver. It's a poor mans NFS that can be a true lifesaver.
You'll have to install it onto the client where you want to mount the folder to. You'll have to install it onto the client where you want to mount the folder to.
This can be done as follows, `sudo apt install sshfs`. This can be done as follows, `sudo apt install sshfs`.
@ -365,6 +366,43 @@ bigone.ovpn configuration gitea.service homeserver.yaml linux64.out
➜ ~ git:(master) ✗ ➜ ~ git:(master) ✗
``` ```
Nice no?
You can even add these mounts to your `/etc/fstab` file!
## SSHuttle
SSHFS gives us a poor man's NFS and SSHuttle a poor man's VPN.
Again, this is very handy additional program to install on your ssh **client** which requires no modifications to the ssh **server** you're connection to.
You install it with trusty old `apt`, `sudo apt install sshuttle`.
Now, what does it do?
It creates a connection to a **remote** ssh server and adds **local** iptable rules to send all (or some) traffic via that remote server onto the internet.
In practice it behaves as a VPN.
To test this out I added an for you to one of my remote servers.
Use the private key I'll give you in class to authenticate yourself as student@sproutsin.space.
The syntax is as follows.
```
➜ ssh-keys git:(master) ✗ curl icanhazip.com
85.28.111.118
➜ ssh-keys git:(master) ✗ sshuttle -r student@sproutsin.space -x sproutsin.space 0.0.0.0/0 --ssh-cmd 'ssh -i student' -D
➜ ssh-keys git:(master) ✗ curl icanhazip.com
51.195.42.244
➜ ssh-keys git:(master) ✗ killall sshuttle
➜ ssh-keys git:(master) ✗ curl icanhazip.com
85.28.111.118
➜ ssh-keys git:(master) ✗
```
This might look a bit intimidating but I'll break down the command line options a bit.
* `sshuttle` is the program you're using to create the VPN (it's a python3 script)
* `-r student@sproutsin.space` is the remote host you want to send your traffic to
* `-x sproutsin.space` is needed to exclude traffic to *that* specific host (the connection would fail otherwise)
* `0.0.0.0/0` is the IP range you want to send through the VPN, in this case it's everything
* `--ssh-cmd -i student` is needed to specify our specific private key (not needed if you use `~/.ssh/id_rsa.pub`)
* `-D` will daemonize the VPN so you can continue to use the shell
## Tweaking the sshd configuration file ## Tweaking the sshd configuration file
All server configuration is done in the `/etc/ssh/sshd_config` file. All server configuration is done in the `/etc/ssh/sshd_config` file.
@ -396,5 +434,3 @@ Protocol
## Autossh ## Autossh
## SSHuttle