Copying files through an intermediate server?

Question

SSH

There are three machines, all running freebsd. #1 and #3 have no connection between themselves, but there is a connection through #2 (networks are different). How to copy a very large amount of data from #1 machine to #3 using #2? The data is measured in TB, so leaving it intermediate at #2 is a bad option.
I tried to do it through mc to #2, on the left side of which there is a connection to #1, and on the right side to #3. But after a number of files, mc constantly gives the error "No space left on device (28)", implying #3, but this is of course not true.
What other ways are there?

Answer 1

I would try scp, but I don't think it would be much different than your mc copy.
In any case, you can always do ssh tunneling.

Answer 2

Try to temporarily set the route so that #1 sees #3 and copy via ftp or scp, as suggested above.

Answer 3

Through ssh, you can try this, for example:
[email protected]:~$ tar -cv files/ | ssh [email protected] "ssh [email protected] 'tar -xv' "

Answer 4

ssh I think will not be the fastest option. Maybe tar+netcat over an OpenVPN tunnel? You can raise tunnels in both directions at #2 and make a bridge on them.