When copying a file between two remote hosts (scp host1:/path/to/file host2:/path/to/file), it is the equivalent of: ssh host1 'scp /path/to/file host2:/destination/path' If you are using locally-defined nicknames for hosts (from ~/.ssh/config), the copy to host2 will fail if the nickname is not defined in host1's ~/.ssh/config. Perhaps, the user can specify a command line argument to optionally have the local instance of scp can pass the locally-defined parameters for host2 (if it exists in ~/.ssh/config), to the ssh process being spawned on host1...
Sorry, but this would add a fair amount of complexity to something that doesn't work very well already and would probably break working configurations if we went ahead and implemented it.
Change all RESOLVED bug to CLOSED with the exception of the ones fixed post-4.4.