If I set up backup nas as target and bring it in office it works (the Synology just uses rsync and listens on 873) If I bring backup nas home and forward port 873 to outside and tell master nas to ...

(I've posted this on their forum, too, but activity is low and there seems to be some kind of moderation queue) I'm trying to set up rsyncd on the NAS and allow anonymous access. I'm 99.9% sure that ...