I'm working in a small company, up to 30 Internet connected devices. Since a few weeks we observe that our Internet connection is much slower than earlier. Browsing pages, downloading files is ~50-300 kbps. But when I download e.g. Ubuntu via torrent it is ~8000 kbps.
My ISP told me that our average network traffic is on the same level as always. And also asked me to do speed test on http://www.speedtest.net to the trusted server. The result was ~40Mb/s up- and down-link, but to the others it is ~4-5Mb/s.
Could you give me any hint how to investigate this problem?