Scp through ssh tunnel opened

Question

I want to send files from machineA which has opened a reverse tunnel with a server. The reverse tunnel connects port 22 on machineA with port 2222 on the server:

autossh -M 0 -q -f -N -o "ServerAliveInterval 120" -o "ServerAliveCountMax 1" -R 2222:localhost:22 userserver@server.com 

If I do:

scp file userserver@server.com:.

then SCP sends the file with a new login over SSH, in my case using public/private key.

But if I do:

scp -P 2222 file userserver@localhost:. 

I get a "connection refused" message. The same happens if I replace 2222 above with the port found with:

netstat | grep ssh | grep ESTABLISHED

How I can send files without opening a new ssh connection (without handshake)?

Answer 1

You can use ControlMaster option in your ssh_config (~/.ssh/config), which will create persistent connection for further ssh/scp/sftp sessions. It is easy as pie:

Host yourhost
  Hostname fqdn.tld
  Port port_number # if required, but probably yes, if you do port-forwarding
  ControlMaster auto
  ControlPath ~/.ssh/master-%r@%h
  ControlPersist 5m