Can anyone recommend some good tools or even just a methodology for tracking down intermittent timeouts/delays on a network? I have a client who complains of timeouts and slowness to web pages. They'll wait a moment, refresh the page and then it will load just fine. Seems to happen across all web pages and from most if not all of their machines. I've tested their bandwidth and they're getting their contracted rate on d/l and u/l speeds which should be more than enough for their size.
They also complain about losing connection to some internal network shares so I believe the issue is probably internal. Their switches are not optimally cabled, and they have a larger-than-I-would-recommend broadcast domain (one flat network using /23 SM), so I'm thinking these issues could be caused by broadcast storms, excaberated by the less than optimal cabling (switch to switch to switch instead of hub and spoke).
I'm having a hard time replicating the issue when I go in to test, due to the intermittent nature of it, but I have seen it firsthand. I'm wondering if anyone can recommend some good software (preferably free) that I can use to analyze their network to see if they're getting an inordinate amount of broadcast traffic, or that could give me any other clues on how to proceed to track this issue down. I've used Wireshark before and could probably capture using that and then filter just the broadcast traffic, but not sure how to tell how much is too much. Any advice on any of this is highly appreciated.