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Running scp through ssh tunnel

Ki H. Kim
Director, Engineering

Run scp to machine R, which is only accessible through gateway machine G.

Step 1: Establish SSH tunnel. Pick a temporary port between 1024 and 32768 (1234 in this example). Port 22 will be used by scp.

$ ssh -L 1234:<address of R known to G>:22 <user at G>@<address of G> 
# Adding "cat -" will keep it running while above will get you connected to G
$ ssh -L 1234:<address of R known to G>:22 <user at G>@<address of G> cat -

Either way you run it, open another terminal for next step.

Step 2: Run scp against port 1234 pretending 127.0.0.1 (localhost) is the remote machine R, and the command will be sent to R.

$ scp -P 1234 <user at R>@127.0.0.1:/path/to/file file-name-to-be-copied

References:
http://whoochee.blogspot.com/2012/07/scp-via-ssh-tunnel.html
http://www.mpcdf.mpg.de/services/network/secure-shell/ssh-tunnelling-port-forwarding

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