Staying after hours and doing some more testing regarding MAC and IP conflicts.
Just shut down the server, and tried to ping it after cleaning my machines ARP. Can not ping 192.168.1.2 and wont get an entry in ARP either, which would suggest that i dont have MAC nor IP conflicts.
Checked ARP tables on the server, router and few random PCs, all seems correct.
Originally Posted by Thorn-Blade
The other thing I would try is to ping the "problem" device from a host that is plugged into the same switch when you are having the problem. Since both of these devices are on the same subnet the traffic should be switched based on the mac table, and the traffic will never leave the switch.
If you can ping it from the same switch, I bet you have a layer 3 issue. Over all I do think this is network related though.
Have you always had this problem since you took over management?
As mentioned before, if the probem is occuring, it is occuring for only a single host to the server connection. Server communicates with everyone else, and the host communicates with everyone else, but they cant communicate between each other for a few minutes, then if fixes itself again and the server picks a different host.
UPDATE: Ran wireshark on the server. Apparently EVERY single packet that was leaving the server had a bad checksum. Found out that the NIC on the server had checksum calculation off-loading turned on and it didnt work. Turned that off and now every packet leaving the server has a correct checksum. Could this have caused it?
Continuing testing, see if the problem persists even after this.