ā03-04-2024 11:26 AM
We have a C9200L-48P-4X deployed. All of the gigabit ethernet interfaces are on one vlan. Most of the interfaces pass traffic just fine but there are at least 4 interfaces (that we know of) that don't pass traffic. All of the interfaces are configured exactly the same and none of them were shutdown or disabled. We first noticed an issue because the PCs connected to the affected interfaces couldn't connect to the domain. When we switched the interfaces that the PCs were connected to, they could connect to the domain with no issues. Any ideas as why this might be happening?
I've attached the interfaces from sh run. The affected interfaces are 25,27,28,30 but their configurations aren't any different than the others.
ā03-04-2024 12:01 PM
show spanning tree
are the port is FWD or BLK ?
show interface status
are the port is a-full a-speed and connect or not ?
MHM
ā03-04-2024 01:18 PM
The spanning tree shows FWD for all ports
The ports are on auto speed
ā03-04-2024 01:44 PM
show interface x/x accounting <<- if you see packets IN and OUT then the port forward the traffic
MHM
ā03-04-2024 01:40 PM
Hello @jeffwill1345 ,
can you provide the output of the show interface Gi x/y command of the interfaces that are not passing traffic?
ā03-04-2024 01:54 PM
What firmware is the switch on?
What is the uptime of the offending switch?
Is this switch part of a stack or standalone?
ā03-04-2024 01:59 PM
Thanks for the help everyone! We're going to be rebooting the switch. I'll let you guys know if the problem still occurs after that.
ā03-04-2024 02:13 PM
@jeffwill1345 wrote:
We're going to be rebooting the switch.
The switch will need to be cold-rebooted, i. e. power cable and power supplies will need to be removed.
Depending on the firmware version of the switch, this exercise will need to be performed every 6 months or when this same issue re-occurs.
ā04-22-2025 09:15 AM
Do we know if the reboot fixed this issue, I have some C9200L-48-4G switches that are experiencing the same issue, the ports that have stopped working were connected to the same devices (Paxton Net2 Plus door access controllers) they have been moved to other ports and are now working without issue. We have been troubleshooting with a laptop, it connects to the port that doesn't work and the port comes up/up connected and we can see the laptops MAC address in the switches MAC address-table, the laptop Arps out for DHCP and an address is provided however the laptop does not receive the IP address. ARP on the L3 device sees what would be the laptops IP and MAC address. Pings to/from the laptop fail to/from the L3 switch SVI for the vlan.
ā04-22-2025 03:06 PM
@stuart.pannell wrote:
they have been moved to other ports and are now working without issue.
What firmware is the stack running on?
What is the uptime of the each individual member of the stack?
Perform a cold-reboot of the offending stack member having port issues. NOTE: Cold-reboot is removal of all power supplies (and power stacking cables) off the offending switch member until the PS stops spinning on it's own. Put the power supplies back in and re-energize.
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