How to automate a vnc+ssh solution

Question

I would like to run an application (call it firefox) on my work machine. The problem is that I need to do some complicated ssh tunelling to get access to it as access to the machine is blocked from the outside and some ports are also blocked internally. So I do the following.

ssh -v -L 1200:serverC:22 user@serverB (locally)
ssh -v -L 5900:127.0.0.1:5900 -p 1200 user_from_serverC@127.0.0.1 (locally)
x11vnc -safer -localhost -nopw -once -display :0 (on serverC)
vinagre localhost::5900 (locally)

I then run firefox (say) in the vnc window that opens and it all works.

However I would like to have a bash script that does this for me. How can I automate it?

There are two problems.

1. I need to stay logged in after each ssh above for the tunelling to work so a simple bash script just stops after the first step.
2. I don't know how to get an application to run automatically in a vnc window.

Ideally I would just type "./remote-firefox" (for example) locally to get all this to happen.

Answer 1

Try:

x11vnc -safer -localhost -nopw -once -display :0 #Run manually on system_C

& on local system,

ssh -t -L 5902:localhost:5901 user_B@server_B 'ssh -t -L 5901:localhost:5900 user_C@server_C' &
#Note: Enable password-less (key based) authentication from "your_pc -> servB" & "servB -> servC"

vncviewer localhost:2 #Run on local system

NOTE: If the commands fail, please try changing the port numbers. In this example, I am trying to tunnel it as below:

your_PC:5902 <-> server_B:5901 <-> server_C:5900

---

I have not tested this 2 level chain (I do not know if x11vnc's -display parameter works across ssh, but I think, it should.):

#Run both lines on local system
ssh -t -L 5902:localhost:5901 user_B@server_B "ssh -t -L 5901:localhost:5900 user_C@server_C 'x11vnc -safer -localhost -nopw -once -display :0'" &
vncviewer localhost:2

EDIT: To accomodate this:

yes that's it. But annoyingly servB -> servC has port 5900 blocked. – Anush

#Run both lines on local system. This may be overhead, but should work.
ssh -t -L 5902:localhost:5901 user_B@server_B "ssh -t -L 5901:localhost:1200 user_C@server_C 'ssh localhost -L 1200:localhost:5900 & x11vnc -safer -localhost -nopw -once -display :0'" &
vncviewer localhost:2