There are various ways, how to SCP through intermediary nodes, e.g. ProxyCommand (using netcat = nc), ProxyJump (scp -J), pipes, tunnels, ...
There is a new project hopscp, doing it without any of them, but prospectively may incorporate them in the future too, to make its possiblities wider.
By default, in its initial version, it is implementing this multi-hop SCP by sequential secure copying through whole chain, from source to target. Current maximum is:
[source_end] -> [source_hop] -> [local_host] -> [target_hop] -> [target_end]
For more information, download hopscp, read its heading synopsis, or run it to see its output in command-line.Software license: The Unlicense.
