Transferring files between servers on a private network?

[Brian Candler]

On 09/12/2020 19:49, Steve Dondley wrote:
> Very interesting food for thought. So let me make sure I understand 
> what I need to do here as I try to reverse 2 decades of cluelessness 
> (I literally never heard of agent forwarding until last night):
>
> So I'll add the pem file with ssh-add on my local machine and then 
> I'll be able to log into C and then once in C I can run the scp 
> command to move files between B and A via the private network. Have I 
> got that right?

Yep, as long as you've enabled agent forwarding (-A)  when you login to C.

With agent forwarding, an agent socket appears on host C.  Any command 
you type there (such as "ssh B" or "scp B:foo A:bar") is able to talk to 
the agent socket, as if ssh-agent were running on host C.

But in reality, the agent messages are passed back and forth over the 
ssh connection between your local host and C, to the ssh-agent running 
on your local host.  Hence your private key never leaves your local host.