I make some files available for download on my website, but there are many who copy the link and distribute them on third-party websites. Can I block access from a third-party website and only leave mine?
If you share via a link:
Administration settings - Administration - Sharing
Dosable “Allow resharing” and check the items below that.
that probably would save you from someone from your own server re-sharing a shared file with someone else.
But what if you would share files via an external link?
That was one of the reasons why I asked how TS shared their files.
A file shared to internal user can be re-shared or not, if re-share is forbidden.
If you send a link of a shared file or folder to an external person, you will have no control, whether it will be forwarded worldwide or not.
It just is a link with password and everybody, who gets both can view or download the linked file/folder.
“Out of organisation” = “Out of control”.
So the question in #1 only is sensible, if you share within the organisation.
You could try to use the HTTP_REFERRER to limit access to just links from your sites via your webserver directly.
It might perhaps be possible to use the file access control, but I’m not sure if that parameter is available:
look at this option Request URL here: Files access control — Nextcloud latest Administration Manual latest documentation