Remot rsync setup: Error connecting to ...

milks wrote:
rsync -avh test pi@192.168.0.170:/mnt/usb_hdd I do get an error 'Connection refused (111) rsync error: error in socket IO (code 10) at clientserver.c(122)' if I use a double colon in the command (not sure what this is doing differently): rsync -avh *.sh pi@192.168.0.170::mnt/usb_hdd

The double colon means to connect via rsync deamon. A single colon will use a remote shell. Thus, there seems to be no rsyncd running on your RPi. Or, there it listens to the wrong ip address or wrong port or the port is blocked by a firewall. You could use "netstat -tlpen" on the RPi to check whether there is a rsyncd listening on the local address 0.0.0.0:873.