l33tsource

Sometimes random blog posts appear.

© 2024. All rights reserved.

Ssh Port Forwarding

15 Jul 2022

This is a short blog post explaining how to forward a port trough a jump host. I needed this to access a web UI which was only accessible via a jump host.

Here is the situation:

+---------------+   +---------------------+    +----------------------------+
|               |   |                     |    |                            |
| You (Host A)  +-->| Jump Host (Host B)  +--->| Target Host (Host C)       |
|               |   |                     |    | Web interface on port 443  |
+---------------+   +---------------------+    +----------------------------+

To make it convenient we add most of the config into .ssh/config

Host HostB

Host HostC
  ProxyJump HostB

In reality you usually have some key and hostnames to configure:

Host HostB
  User userb
  Hostname 192.168.1.1

Host HostC
  User userc
  Hostname HostC
  IdentityFile /home/userc/.ssh/keyfile
  ProxyJump HostB

And thats all now we can forward a port from HostC by calling this:

ssh -N HostC -L 8000:localhost:443

And we can access the web UI from HostC on localhost:8000.

Related Posts