Table of Contents

— Marc Verhaar 2021/12/19 13:46FIXME

SSH tunneling:

Local portforwarding:

Using the ssh server as a jumphost for a service in the ssh server network:

We can establish these connections like this: 

 ssh user@server -L 12345:192.168.1.200:81

This will open an SSH session and as long as it runs the tunnel is active!

You can now open a local browser to http://localhost:12345 and it will open 192.168.1.200:81 on the network where the SSH server is located.

Remote portforwarding:

FIXME

Dynamic portforwarding with SOCKS proxy:

Install ''proxychains:''

 sudo apt install proxychains -y

Edit /etc/proxychains.conf on **client** and in the **ProxyList** section set the port:

[ProxyList]
# add proxy here ...
# meanwile
# defaults set to "tor"
socks5  127.0.0.1 9050

Use socks5 which supports encrypted tunnels and UDP protocol!

Now we can set up the SSH tunnel:

ssh user@server -D 9050

This will open an SSH session and as long as it runs the tunnel is active!

We can now use the SSH tunnel with any application that supports SOCKS:

Webbrowsers do support this but we need to configure the proxy configuration according to the tunnel:

We now can connect directly to the servers in the SSH Server network:

Using SSH Jumphost:

We can use an SSH Jumphost to connect to an SSH server: 

ssh user@server -J user@jumphost
example:
ssh root@192.168.1.70 -J marcv@verhaar.cc

Using multiple jumphosts: 

ssh user@destination -J user@jumphost1 user@jumphost2

FIXME: using ssh config file for jumphosts…

Example config file:

We can create a configuration file for the ssh client which is used to define hosts, usernames, portnumbers, etc.

The file needs to be created in ~/.ssh/ thus the full path is ~/.ssh/config. 

Host myserver                                      # The name you want to use to connect
  Hostname 192.168.1.10                            # The IP address the hostname needs to be translated to
  Port 22                                          # The port you want to use
  User marc                                        # The username used to set up the connection