Showing posts with label filetransfer across server. Show all posts
Showing posts with label filetransfer across server. Show all posts

20 April 2012

121. Connection to remote server via an intermediary server

We have three computers: A, B and C

A is our desktop. C is a remote computer we want to connect to. B is a server in the middle.

For various reasons we want to first connect from A to B, then from B to C. A scenario is where C is behind a firewall bridged by B.

A specific scenario is this:
I have a linksys router, e.g., which manages the network in a lab. There are several computers on the network in the lab behind Terbium: Sulfur, Phosphorous, Oxygen ( etc.
My home computer is Niobium.

Terbium is a linksys router (W54G) running tomato and you have to log in as root using a keyfile.
Oxygen is a debian box where I have a personal account as user verahill.

The ugly method:
In the same terminal on computer Niobium do
ssh verahill@

This works fine for working remotely on oxygen ( However, file transfer is a pain

The pretty method:
In one terminal on Niobium, do

ssh -L 9999:

In another terminal on Niobium, do
ssh verahill@localhost -p 9999

Basically, all traffic to port 9999 on niobium is forwarded to port 22 on Oxygen -- not terbium.

The cool thing? File transfer is a breeze (via sftp using e.g. filezilla)!

It really is that simple

Web tunnel
to browse the internet via a tunnel it's still easier to do
ssh -C -D 9889
and set your browser to use a SOCKS proxy -- point it to localhost, port 9889.