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This is an extension of the question by @Andrei

How to mount remote SSHFS via intermediate machine? Tunneling?

I'm in the same situation that I want to mount a remote directory, however the difference is that both machines A and B are not publicly exposed on the internet. A is my local work station.

So I can neither ssh from A -> B, nor B -> A.

What I regularly do, is establish a reverse connection from B -> C, where C is a rented virtual server (VPS). A script doing this connection (and reconnecting in case of lost connection) is started via the @reboot key of cron.

user@pcB $ ssh -R 2048:localhost:22 -p<port> user@serverC

Then, to go from A -> B I take the intermediate route A -> C -> B.

user@pcA $ ssh serverC
user@serverC $ ssh -p 2048 user@localhost
user@pcB $ # okay, logged in.

I'm looking for a way to mount the directory pcB:/home/user on pcA.

How do I connect to a pc through another pc using ssh is similar, but the solutions provided don't work in this scenario: the connection map in my case is A -> C <- B not A -> C -> B.

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Sebastian
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1 Answers1

6

This was easier than I thought!

All one has to do is bind the port 2048 of serverC to a port on pcA. For simplicity I use the same port number 2048:

user@pcA $ ssh -L 2048:localhost:2048 user@serverC

One needs to keep this terminal window open.

Then, mounting the directory pcB:/home/user locally on pcA looks like this:

sshfs -o port=2048 user@localhost:/home/user/ /mnt/pcB

Nice side-effect: This means you can also use efficient X-server connections, e.g. freeNX or vnc to retrieve a display of pcB. Just connect to localhost:2048 and use the correct credentials (user name/password) for machine pcB!

If you don't want to have to keep a terminal open for the connection, you use:

ssh -NfL 2048:localhost:2048 user@serverC

Note that doing this might violate your employers'/organizational security policy, so make sure to get appropriate permissions.

Lifeboy
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