I hope someone will be able to help with the weird problem we start
Experiencing a few weeks ago:
Our LAN setup:
We have close to 70 servers on the LAN network, connected to main Cisco 3750 stack switch on the 5th floor.
Flat structure, no VLANs configured.
Software version is c3750-ipbasek9-mz.122-35.SE2
We have Dell PE servers various models.
Network cards are Intel or Broadcom, configured as a Team with Failover redundancy.
3750 stack has 9 switches.
There are also other 3750 stacks on other floors of the building connected with SPF connectors to the main switch.
One C2950 switch in the test lab, is up linked to main 3750 stack.
Intermittently server1 (S1) cannot ping S2?and vice versa?
S2 is pingable by S3, S4 and other servers at the same time.
S3 and S4 can ping S1 as well?.
In general this can happen every 10-15 min and last for a minute or two?
Sometimes one of workstations involved when they can?t ping one of the servers, but can ping other servers fine?.
If I am logged on the main 3750 switch, and during the ?outage time? I ping the server that does not reply, it restores connectivity right a way?..
Seems that switch does not retain MAC entry of ?culprit? server, or workstation.
But I am not an expert???..
If I reload the main 3750 stack, then it can fix some ?culprits? but eventually there will be new.
What has been done:
Software was upgraded to c3750-ipbasek9-mz.122-35.SE2
Built in diag did not show any issues.
We unplugged every second NIC card on the servers; they run on single NIC card
Cisco TAC team worked with us to no result so far
All non-Cisco equipment (linksys personal switches, D-links) are disconnected.
Since we unplugged every second card, problem re-appears less often, I think we run fine for a few days, but it is still shows up occasionally, as a few users reported it.
PS: Servers Event logs do not show any related info.
I hope someone had seen this before, or knows the solution.
What could cause it?
Any help greatly appreciated