1. Changed the switch in the problem building for another.
2. Tried a different port on the new and old switch for the fibre patch cables.
3. Changed the port the server uses on the main network switch.
4. Re-started all switches by turning the power off and back on.
5. Re-started all the servers.
6. Took a machine from a part of the site that is fine, plugged it into the switch in the problem building. But then this machine has the same problem. Back in it's normal "home" it is fine again.
7. On one of the problem machines I released the IP settings using ipconfig, deleted it's DHCP lease in DHCP and then restarted the machine. Same problem again.
For all the world it appears to be a configuration or software issue on the "problem" server, because the uplink cable back to the main network switch is clearing working. But what the problem is I don't know.
Here is a link to a "crude" network diagram showing the setup - http://www.ldbsa.co.uk/images/net_setup.png
The computers in the building on the left in the picture are able to access 4 of the 5 servers in the server room, but not the fifth. The other 4 buildings on the site are able to connect to everything without any problems at all.
Does anybody have any suggestions?
Edited by alsit, 09 January 2013 - 09:42 AM.