09-11-2014 06:46 AM - edited 03-07-2019 08:43 PM
We are running Cisco 4500 chassis at the access layer, and have been for a few years without issue. Recently we started to experience issues where a mac address will just randomly "jump" to another port. User will call us and say their computer is not working. We will locate the mac, and its showing on the wrong port. We shut that port, do a no shut, and the mac jumps back to the correct port. In the example below, the mac address jumps to port 3/2, but is physically connected to 2/12.
!--issue before shut/no shut
mdf#show mac address-table | inc 9ebf
236 782b.cb8c.9ebf static ip,ipx,assigned,other GigabitEthernet3/2
!--port security knows the correct info however
mdf#show ip dhcp snooping binding | inc 9E:BF
78:2B:CB:8C:9E:BF xxx.xxx.236.193 76145 dhcp-snooping 236 GigabitEthernet2/12
mdf#show mac address-table int gi2/12
Unicast Entries
vlan mac address type protocols port
---------+---------------+--------+---------------------+-------------------------
3908 20bb.c021.ae58 static ip,ipx,assigned,other GigabitEthernet2/12 !--ip phone
mdf#show mac address-table int gi3/2
Unicast Entries
vlan mac address type protocols port
---------+---------------+--------+---------------------+-------------------------
236 1803.7339.d93d static ip,ipx,assigned,other GigabitEthernet3/2
236 782b.cb8c.9ebf static ip,ipx,assigned,other GigabitEthernet3/2 !--mac in question
236 782b.cb8c.c366 static ip,ipx,assigned,other GigabitEthernet3/2
3908 b414.89a2.2ae0 static ip,ipx,assigned,other GigabitEthernet3/2
!--fixing issue
mdf(config)#int gi3/2
mdf(config-if)#shut
!-- issue resolved
mdf#show mac address-table | inc 9ebf
236 782b.cb8c.9ebf static ip,ipx,assigned,other GigabitEthernet2/12
Switch is running cat4500e-entservicesk9-mz.151-2.SG2.bin , but also happened on cat4500e-entservicesk9-mz.151-2.SG4.bin and cat4500e-entservicesk9-mz.150-2.SG4.bin. Other switches have also had this issue occur.
09-11-2014 07:21 AM
Looks to be me like a bug.
could you please provide me some more details on this:
1- How often this issue is occurring?
2- Is this occurring to specific ports or specific laptops which are connecting to this ports or is it irrespective of devices?
3- Is there any possibilities that you try rebooting one of the switch if the issue is very often? (I know this is not a feasible solution , I know it is some issue iwth the firmware but in case to avoid high impact you can reboot the switch and update me?
4- Provide me with the logs from the switch?
5- I will do the bug scrub and let you know.
HTH
09-11-2014 07:37 AM
Issue is occurring daily? Kinda tough to tell since we are relying on users to notify us.
We run mostly dells, and as far as i know, they were all dell desktops. Not sure of the model. Some ports have Cisco phones that the computers are connected to, other ports just have the desktops connected directly.
We rebooted the switch in the example this morning, and the issue appeared an hour later. The issue happened with every version of code i listed on this switch. We rebooted a few other switches and the issue re-occurred.
I can provide logs, but what logs to you need?
09-11-2014 07:42 AM
Show tech would be good.
If you think you cant share public send it to me via private.
09-11-2014 08:45 AM
pm sent
09-11-2014 09:01 AM
Just to add to the complexity, we just had another issue pop up on a switch that hasnt had a problem before. In this case however, I removed the switchport port-security off the port and the computer was able to get an ip instantly. I did not shut/no shut the port.
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