4

I want to copy a file from server-a to server-d but I can access server-d only from server-b and then to server-c. server-a can only access server-b, server-b can only access server-c, server-c can only access server-d..

Currently I do it like this:

server-a> scp /tmp/file.txt user@server-b
server-a> ssh user@server-b
server-b> scp /tmp/file.txt user@server-c
server-b> ssh user@server-c
server-c> scp /tmp/file.txt user@server-d

This could be through 5,6,7,.. servers

Can I do this is one command?

5

You need the ProxyCommand, see the man page. Here's an example:

Host serverB
HostName serverA.com
User someuser
ProxyCommand ssh -q serverB -W %h:%p  # -W is supported by a recent OpenSSH
# or for older versions or other implementations
# ProxyCommand ssh -q serverB nc %h %p

This allows you to type ssh serverB and you connect to serverA which then connects to serverB. This can easily be extended to work with 𝑛 host. It will work with scp the same way it does for ssh.

  • I only can use the ssh command not the ~/.ssh/config file. Does this command should work ssh -o ProxyCommand="ssh -o ProxyCommand=\"ssh user@server-d\" user@server-c" user@server-b ? – Nir Sep 16 '13 at 13:12
  • Should work. You can also use alternate config file through the -F option. – peterph Sep 16 '13 at 19:58
1

your best bet is probably to build up tunnels, and then cat the file through oll these tunnels:

cat file.txt | ssh -A -t user@server-b \
   "cat | ssh -A user@server-c         \
      \"cat | ssh -A user@server-d     \
         \\\"cat > /tmp/file.txt\\\"   \
      \"                               \
   "

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