Solved: Re: Connection to CIMC lost after changing the NIC mode to Cisco card

JOKERR · ‎08-07-2021

Hello,

I was checking the network settings and decided to change the NIC mode to Cisco card. Previously CIMC mode was set ot Dedicated. After changing, I clicked save. Now the CIMC will not be pingable at all. I can still access the ESXi host and create VMs. CIMC is not responding.

I am very new to this and have following questions:

1. Did I mess anything up by changing the NIC mode? Why did the CIMC IP became unreachable?

2. Since I have access to the ESXi, is there any way I can change the NIC mode to dedicated from ESXi? Or anything I can do from the ESXi at all to bring up the CIMC?

Thanks in advance.

RedNectar · ‎08-07-2021

Hi @JOKERR ,

UCS C-series servers have two regular ways of accessing the Cisco Integrated Management Controller (CIMC)

Dedicated (usually the default). In this mode you access the CIMC via the dedicated CIMC interface - i.e. plug a cable into it.
- Note: This mode has variations based on the Shared LOM setting
Non-dedicated. In this mode you use "single-wire" mode - the CIMC is accessed via one of the (typically two) 10/25/40G Ethernet interfaces that are also used for for user traffic and connected directly to a Cisco Fabric Interconnect.

The fix is not that hard, but may not be what you want to hear. To set it back to Dedicated mode:

Connect a keyboard and monitor to the server and re-boot it (that's probably what you did NOT want to hear)
As it is re-booting, hit F2 to enter the BIOS configuration
Set the BIOS setting for Dedicated mode (Sorry for the mocked up screen dump, my original showed Dedicated unset)
Hit F10 to save

I hope this helps.

Don't forget to mark answers as correct if it solves your problem. This helps others find the correct answer if they search for the same problem.

RedNectar aka Chris Welsh.
Forum Tips: 1. Paste images inline - don't attach. 2. Always mark helpful and correct answers, it helps others find what they need.

View solution in original post

RedNectar · ‎08-07-2021

Hi @JOKERR ,

UCS C-series servers have two regular ways of accessing the Cisco Integrated Management Controller (CIMC)

Dedicated (usually the default). In this mode you access the CIMC via the dedicated CIMC interface - i.e. plug a cable into it.
- Note: This mode has variations based on the Shared LOM setting
Non-dedicated. In this mode you use "single-wire" mode - the CIMC is accessed via one of the (typically two) 10/25/40G Ethernet interfaces that are also used for for user traffic and connected directly to a Cisco Fabric Interconnect.

The fix is not that hard, but may not be what you want to hear. To set it back to Dedicated mode:

Connect a keyboard and monitor to the server and re-boot it (that's probably what you did NOT want to hear)
As it is re-booting, hit F2 to enter the BIOS configuration
Set the BIOS setting for Dedicated mode (Sorry for the mocked up screen dump, my original showed Dedicated unset)
Hit F10 to save

I hope this helps.

Don't forget to mark answers as correct if it solves your problem. This helps others find the correct answer if they search for the same problem.

RedNectar aka Chris Welsh.
Forum Tips: 1. Paste images inline - don't attach. 2. Always mark helpful and correct answers, it helps others find what they need.

JOKERR · ‎08-08-2021

Thank you RedNectar.

It was just installed and I was tweaking the settings around. Should have researched this before changing the NIC mode. Need to visit our lab ti perform this.

Thank you for the insight.