http://nmap.org/book/man-port-scanning-techniques.html - this page lists technique that allows to probe if a UDP post if closed. It would be awesome to see green button that lights up when you complete IP entry in configuration dialog.
ICSdroid is lacking a setting that prevents to sync without wifi. It’d be pretty useful, not just to prevent using mobil data transmission, but also to prevent sync failures, which are possible when not having good mobile connection. Notice DAVdroid does offer the setting.
This is a duplicate of https://forums.bitfire.at/post/12711. Please follow up there. Unfortunately, I don’t know why Android starts synchronization when Internet is not available yet.
