Users are reporting that it's taking a long time to access files on the network, browse intranet sites, etc. What should I check?
To check the latency on a network:
Run a continuous ping from the command line:
ping -t [destination IP DNS or hostname]
If any of these are slow, then run:
tracert [destination IP DNS or hostname]
to see where the issue is.
To check the bandwidth of a network:
You will need to install bandwidth monitoring software, look at your network switches (if they support monitoring), look at router logs, etc.
http://performit.co.uk/network/troubleshooting.php has some good tips.
Check the duplex settings on the network ports.
If one end of a network link is set to 100baseT full duplex, and the other is set to auto-negotiate, the auto-negotiating end will always go half-duplex.
This wouldn't reveal itself with simple ping tests, but any substantial traffic over the link will be a lot slower than it should be.
first tools I would use would be ping and tracert. These will let you know right away if packets are being dropped and where. Routing issues will also bubble up.
I've also seen it where proxies, configured incorrectly, can cause problems on a local network.