X server connected to Cisco 4507 keeps dropping!

[UncleCisco]

We have a Cisco 4507 with a new X serve attached. Every X amount of time (usually around noon) we lose connectivity to the X serve. The port stays active (lights are on) but can't ping across link. This means the LLC part of layer 2 is working but higher level protocols are down right? the only way to solve this is to reboot the Xserve. We have tried to replug the port into the switch, played with the spanning tree portfast settings, both hard-coded and left port duplex/speed to auto, set logging to notification level, and can't come up with any answers. We have tried different ethernet ports on the X serve and have even replaced the mainboard of the server- still crapping out between 1 day and 3 weeks. Anyone else seen this issue?

I have seen IBM servers lose auto negotiation over time but problem is always fixed when hard coded. This is not related. Anything else to try? Would a sniffer be useful in this instance? Any idea what might be happening at around noon to cause a server to drop? The server thinks all is fine but is unable to talk beyond its own port...

Thanks for any help.

 

[baddos]

1.) Make sure both the switchport and the NIC Card are set to auto, or identical settings.

2.) "switchport mode access" and "spanning-tree portfast" should both be set on that interface.

3.) When the server is functioning correcting, do a "show mac-address-table interface gigX/X". Write down the MAC address, then when it "goes down" repeat and see if the mac addresses match. If their are different it's probably an IP address conflict.

4.) Issue a "logging event link-status" on the server's port, so the switch will write an entry if the link is broken or resumed.

5.) Check error counters, and do a "show interface gigx/x" to make sure it's not "administratively down" or posting excess errors.