Scp over a proxy with one command from local machine?

Question

I have my local.machine, the proxy.machine and target.machine. local.machine doesn't have direct contact with target.machine, but needs to go through proxy.machine.

I want to scp a file from target.machine to local.machine. Is this possible to do with just one command from local.machine?

Answer 1

I know this is a late answer, but I just found out a cool way to do this. It is basically Holger Just's answer, but in a saved config file:

You need to put this in your ~/.ssh/config file on local.machine, (creating the file if it does not exist)

Host target.machine
  User          targetuser
  HostName      target.machine
  ProxyCommand  ssh [e-mail] nc %h %p 2> /dev/null

After saving the file, you can just use

ssh target.machine

any time you want to connect. Scp also will work as it also respects the ssh config file. So will Nautilus, if you're using GNOME and want to use a GUI.

Answer 2

You can now* do this as a one-liner, without requiring nc anywhere:

scp -o "ProxyCommand ssh [e-mail] -W %h:%p" [e-mail]:file .

Explanation

pcreds and tcreds represent your proxy and target credentials if required (username, username:password, etc.).

This is possible because of a built-in netcat-like ability, removing the requirement for nc on the intermediate host. Using ssh -W host:port sets up a tunnel to the specified host and port and connects it to stdin/stdout, and then scp runs over the tunnel.

The %h and %p in the ProxyCommand are replaced with the target host and port from the outer scp command, to save you having to repeat them.

For even more convenience, you can configure the proxy in your ssh configuration:

Host target.machine
    ProxyCommand ssh [e-mail] -W %h:%p

and from then on just do

scp [e-mail]:file .

* since OpenSSH 5.4 - released March 2010

Answer 3

You can do it in one command, but you need netcat (nc) installed on the proxy machine:

ssh -o "ProxyCommand ssh [e-mail] nc -w 1 %h 22" [e-mail]

[EDIT: mixed up the order of machines...]

Answer 4

If you don't mind using rsync instead of scp, you can use the following one-liner:

rsync -v --rsh "ssh proxy.machine ssh" target.machine:/remote/file /local/dir/

(you'll need passwordless access to the proxy machine)

Answer 5

$ ssh -f -N -L <localport>:<target.machine:port> [e-mail]
$ scp [e-mail]:/remote/file -P <localport> .

OK, actually two commands...

Answer 6

A one-liner? Not off the top of my head. You need to establish a proxy first and you can't do that with scp by itself.

When doing it manually, I open up a screen session for my tunnel:

screen -S tunnel

Screen is used to keep the tunnel going in a background shell. Use any technique you want to keep the tunnel open in the background (@weeheavy's answer is probably the simplest). Once in the screen session I start my tunnel like so

ssh -L 2222:target.machine:22 [user@]proxy.machine

To break that down, that basically says "On my local machine, open port 2222 and any connetion hitting localhost:2222 is proxied through proxy.machine to target.machine:22"

Once you've got the ssh connection and tunnel established, detach from the screen session with "C-a d". To get back to that screen session, type screen -raAd tunnel

Once you are back in your original shell your scp command will look like

scp -P 2222 localhost:your/file/on/target.machine local/path

Remember that localhost port 2222 is really just a tunnel going to target.machine.

Answer 7

Appears that scp supports the"-o" option just like ssh does, though I'm not sure how to pass it a proxy username/password:

scp -o "ProxyCommand=nc -X connect -x proxyhost:proxyport %h %p" remote_user@remote_host:remote_path local_path

If you get nc: invalid option -- X see https://stackoverflow.com/a/23616021/32453

Answer 8

How about:

scp -o "ProxyCommand ssh [e-mail] nc %h %p" your.filename [e-mail]:/whatever_location

Answer 9

Another simple solution to transfer a source_file from the source_host to a destination_host via a proxy_host:

Log in on the proxy_server:

ssh login@proxy_host

From the proxy server, transfer the source_file from the source_host to the destination_host (you can type this as one line, omitting the \, or as two lines, as shown below):

scp login@source_host:/path_to_source_file \
  login@destination_host:/path_to_destination_directory

This requires that the login on the source_host to the proxy_host uses an rsa_key.

Answer 10

I followed this article and found an answer which works for me. (Because the answers above don't work for me).

How to scp a file through an intermediate host (a.k.a. jump host) http://mperdikeas.github.io/networking.html.files/scp-a-file-through-jump-host.html

And my answer is as below:

scp -oProxyCommand="ssh -W %h:%p {username}@{proxy_IP}" \
        {source_file} {remote_username}@{remote_IP}:{remote_file_path}

Example:

scp -oProxyCommand="ssh -W %h:%p ubuntu@10.60.10.145" \
        archive.gz [e-mail]:/home/wise/archive.gz

I hope this answer could help you.

Answer 11

You could try something like:

ssh [e-mail] "ssh [e-mail] 'cat > file'" < file

But it won't work if your proxy.machine needs to ask you password (that SSH is not in a TTY, so askpass will fail).

If you have more than one file, you could use tar like this (untested, I usually use a netcat that way):

tar cf - file1 file2 folder1/ | ssh [e-mail] "ssh [e-mail] 'tar xvf -'"

Answer 12

In case you need to use public keys you will need something like this.

Host target-machine
  User          target-user
  HostName      target.example.com
  IdentityFile  /path/to/file.pem
  ProxyCommand  ssh bastion -W %h:%p

Host bastion
  User         bastion-user
  HostName     bastion.example.com
  IdentityFile /path/to/file.pem