We have a 10 user network that for the last few weeks has been really slow, not all the time, but most of it. The first sign was slow internet, but if we disconnected the LAN and plugged a laptop straight into the router it worked fine. We have a Draytek router so we enabled syslog, this did not show anything obvious - it seems that the problem causing the slowness is within the lan - ie the traffic never gets to the router.
We replaced the switches, had no effect.
We have run Wireshark to try and see what is happening on the LAN - but again nothing obvious.
Any other tools/tricks anyone can suggest?