How can I turn on that apache send the download size so that the browser can calculate the remaining time. When I download from my server there is always unkown file size.
Which your server?
http://www.apachehaus.info/images/ferienhaus-seenland.jpg
that one?
After some research it is only in LAN. I'm gonna check my browser at home. Maybe there is that issue.
OK, back to myproblem. That happens only with larger files. There is not AV or firewall on the server installed. And with small files this does not happen.