ssh_tunnels

Shell code to easily create and use SSH tunnels

scenario

There are any number of machines inside the network that you may need to access. You have ssh access to a gateway machine, which in turn has access inside the network.

ssh tunnels

An SSH tunnel provides secure access to the internal machine. I can never remember how to set them up, and anyway I want:

• Stable config, the SSH tunnel to server xyz should always use the same settings
• A "suite" of definitions and behavior, to use a tunnel you need to know its settings

So in this code you define a gateway server:

ssht_gateway_userhost='user@gateway.domain.org'

Then define a tunnel named "box1" mapping localhost:2222 to box1.domain.org:22, which you log into as "someuser"

ssht_define box1 box1.domain.org 2222 22 someuser

Now you have a command that will SSH to the box, setting up the tunnel as needed:

ssht_box1_ssh

You also have variables you can use with SCP:

scp -P $ssht_box1_port $ssht_box1_userhost:/remote/file /save/locally

web tunnels

One really handy use for SSH tunnels is for internal web servers:

ssht_define ws1 ws1.internal.domain.org 8180 80
ssht_ws1_tunnel

Now you can access ws1 directly at http://localhost:8180/.

Directly monitor each server in a cluster:

ssht_define ws1 ws1.internal.domain.org 8180 80
ssht_define ws2 ws2.internal.domain.org 8280 80
ssht_define ws3 ws3.internal.domain.org 8380 80

Easy!