Had another weird problem today, some started saying their internet connection was dog slow, problem was connecting onto their machine using vnc, it all looked fine their didnt appear to be anything wrong with the bandwidth available.
In the end what is was, was that someone had plugged in the wireless access point twice into the same switch, so basically had made a switching loop.
The effect of this could be seen clearly as pinging from one machine to another on the network caused 2 – 3 pings out of 10 to time out. This choppy network performance was clearly causing the problems in the network’s speed.
Other things that can cause problems are network clients such as Novell Netware, at one site all the workstations had the novell client installed even though it was not used anymore. The old novell server was running on the network but was not used for anything anymore, it was mothballed but still connected.
One day there was a powercut and after the power came back on we started to get people saying the network was slow. What they meant was slow was each time they clicked to browse a folder or file on the network there was a 10 second delay on each click.
What was happening was the Novell server was never switched on after the power cut all the workstations were checking this server first and timing out before going to the Windows server.
Switching the server back on resolved the problem, and then also removing the client from all the workstations.
You could also change the provider order by Control Panel->Network Connections selecting advanced from the menu at the top. Selecting Advanced Settings and changing the settings.