I'm having problems with our office network at the moment in that client PCs intermittently lose connectivity to the network. I've added an image to give a rough idea of how things are set up here.
What is happening is this:
- Some computers intermittently lose the ability to connect to servers (shared folders, email server, database server, network apps, etc.)
- Some but not all computers intermittently lose the ability to connect to our router (ping response "192.168.1.1: Destination host unreachable"). Router address is 192.168.0.254. This is of particular inconvenience as we have 25 sites all of which connect to our servers for email and a gift card system which is hosted here in head office (hence customers are inconvenienced also).
- Sometimes when users are able to ping the router, they are still unable to browse to anything except locally hosted webpages (unable to see google but can see intranet) yet they can still ping 'www.google.ie'
and get responses in decent time and can browse to the router's login page. We use OpenDNS for filtered internet access and our ISP's DNS for unfiltered access however this problem is not restricted to one setup or another.
NOTE: We do also however have our own local DNS server which is primerilly used for Domain control, Active Directory, etc. Nearly all computers in the office are set up with this as primary DNS currently.
Up to now, we did not use managed switches, however I had one in stock and purchased the second last week. In an attempt to locate the issue I installed both to see if there was an issue with a particular network card and I have replaced two network cards that I found issues with. I have rotated the connections so that I have now monitored all port connections at least for one day. I have also rotated the 3rd switch (unmanaged) to make sure the switch itself was not causing the problem. I now have two brand new switches and one used but working.
It has been suggested by a friend that there may have been a loop which I can now confidently dismiss as I have checked every port and small switch (used as wireless access points) on the network.
The other suggestion was that there may be a broadcast storm. I have tried a few things to dismiss this idea within the limits of what I can try during working hours but so far with no luck. Is there a good way to go about this?
Or is a broadcast storm out of the equation altogether?
Any other suggestions?
Thanks in advance...