rsync -vae ssh user@host1:/tmp/dir user@host2:/tmp/

[pod]

>>>>> "DX" == Darxus  <Darxus at ChaosReigns.com> writes:

    DX> I have legitimate ssh access to two remote machines.  ssh directly
    DX> from either machine to the other is blocked by firewalls which I
    DX> cannot control.

If you are able to make ssh connections from host1 to home then the method
outlined in

<http://www.mail-archive.com/rsync@lists.samba.org/msg08450.html>

will work to transfer from host1 to host2 via home without writing the
data to disk on home.

I notice that the archive copy has been blatted the command line given in
that message.  Here's the recipe assume that the usernames on all three
machines are identical:

host1$ rsync --rsh ssh --rsync-path 'ssh host2 rsync' srcfile home:dstfile