I am trying to run rsync via remote-shell connection from an Asustor NAS to my Ubuntu server. The command from the NAS is not possible to change since it is run from the web interface. But I know the command that is being run and I can test it manually, which gives an error. It looks something like this when I run it from the NAS:
$ /usr/builtin/bin/rsync -e "/usr/bin/ssh -l ssh-user-on-my-server -p 12345" --progress -a --timeout=60 rsync://firstname.lastname@example.org:873/rsync-module email@example.com's password: rsync: server sent "2017/01/17 19:38:58  connect from xxx-xxx-xxx-xxx-url-to-the-nas.com (xxx.xxx.xxx.xxx)" rather than greeting rsync error: error starting client-server protocol (code 5) at /asustor/branch2_6_2016_09_22/x64_g1/source/rsync-3.0.9/main.c(1649) [Receiver=3.0.9]
I happend to notice that the message above looks exactly like the log format from rsyncd. This is an example output from rsyncd when running rsync from the NAS to my Ubuntu server without SSH:
2017/01/06 23:42:13  connect from xxx-xxx-xxx-xxx-url-to-the-nas.com (xxx.xxx.xxx.xxx) 2017/01/06 22:42:13  rsync on rsync-module/ from firstname.lastname@example.org (xxx.xxx.xxx.xxx) 2017/01/06 22:42:13  building file list 2017/01/06 22:42:14  sent 172 bytes received 24 bytes total size
I have verified that both SSH and rsync works on their own, this problem only happen when I try to run the script, that is rsync via remote-shell connection.
This looks a lot like Rsync with ssh and root not working after change hosts IP, but the problem there was a greeting message from