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Unable to access the CIMC port from the switch

Level 2
Level 2

Good Day All,

I am having trouble accessing the CIMC port from the switch.

It is on an access-port in the dedicated management vlan.

If I connect directly to the CIMC using a cross-over cable, all is fine and I can login to the CIMC via the web browser.

when I plug the CIMC port back into the switch, however; I can no longer see it on the network.

If I connect my laptop to the access port on the switch,  other PCs on the network can see my pc and ping it so the switchport seems to be configured correctly and the cabling is OK.

The IP address configured for the CIMC is on the management VLAN with the correct subnet mask and default gateway.

The NIC Mode is set to dedicated with None on the redundancy settings.

The server host is a C220M3.

I have connectivity to VmWare via the data NIC cards.

I just can not get to the CIMC.

any help would be so appreciated.



6 Replies 6

Level 4
Level 4


Are there any static speed and duplex settings on the managment switch?  The CIMC managment ports currently operate in auto mode for speed and duplex.  If there is a mismatch on the managment switch this may be causing your problem.

Steve McQuerry

UCS - Technical Marketing

Zaira Vega
Cisco Employee
Cisco Employee

Since dedicated mode is selected, did you connect the cable on the appropiate port on the server?

The dedicated port is the 10/100/1000 ethernet, first from left to right, underneath PCIe 1.

Did you selected the option for vlan tag on CIMC config? If you did, try removing it.

Cristian Munoz
Cisco Employee
Cisco Employee


Do you want to have connectivity to VmWare and CIMC using the same ports?

If so, What interfaces are being used for ESXi, the LOM ports or the PCIe adapter?

You can verify that from ESXi to know what the uplinks are:

# esxcfg-vswitch -l



Switch Name      Num Ports   Used Ports  Configured Ports       MTU      Uplinks  

vSwitch0               128                6                          128          1500       vmnicX   

Then choose from the following options:

Shared LOM => If the uplink is one of the LOM ports

Cisco Card   => If you have a cisco vic card and the uplink is one those ports.

Or Shared LOM EXT (default) =>  With this mode, the shared LOM and Cisco Card interfaces are both enabled for management.

Level 3
Level 3

I had the same problem recently.

I Used Management port for CIMC.

In CIMC Configuration Utility (Press F8 during bootup), I set NIC Mode as Dedicated, configured IP address, and Gateway.

Usually this should work in my Lab with a HP server.

For UCS C240 M3, I need to Select VLAN Enabled, and set VLAN ID. After this I got CIMC connection.

Hope this helps


Tomi Hakala
Level 1
Level 1

I have this exact same problem also on our C240 M3 servers.

If I hook up dedicated CIMC port to our C2960S switch CIMC IP address is accessible for 30 seconds or so until it stops responding. Putting CIMC port on shutdown and then up state at switch end reset this issue and CIMC is again accessible for 30 secs or so until it goes dead again.

Once I configured CIMC access to be on shared LOM I can access CIMC OK, until shared LOM moves CIMC access to a ports which are configured for LACP and it stops working again. So not quite perfect situation for us.

I had support case open for this, but it did not resolve anything as access to a CIMC works if I connect my PC directly to a dedicated CIMC port. SR was 626466795 if any Cisco employees are interested in checking it up.

I think this problem is somehow related to our VLAN configuration on the switch end. We are running CIMC management access on VLAN 1 on the switch, I guess this is causing some kind STP loop or some else issue when dedicated CIMC port and shared LOMS are connected to a same switch. Although I cannot see any error messages related to this on the switch end. Once I have enough time, I will reconfigure our network to not use VLAN 1 and see if it has any change.

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