After update, no connectivity on 'main' NIC

[ruben.urresti]

Motherboard: Supermicro X12SPA-TF -> has 3 LAN ports (one is used by the onboard IPMI)
Proxmox: Version 8

The strange things that happened months ago:
When I first installed this machine a couple of months ago, I already had some trouble ensuring that all network-related functionalities remained operational after every reboot. I believed this was due to the NICs' names changing after a reboot. To prevent this, I created two files in /etc/systemd/network/ that assign specific names to interfaces, as shown below. While this resolved some instability, it wasn't completely reliable. Occasionally, after a reboot, internet connectivity would be lost, and my Proxmox UI would be inaccessible at 192.168.20.201:8006, as it normally should be. However, despite these issues, it was somewhat functional and continued to work for months.

$: cat /etc/systemd/network/90-eth0.link

[Match]
MACAddress=3c:ec:ef:99:70:2d

[Link]
Name=eth0

$: cat /etc/systemd/network/91-eth1.link

[Match]
MACAddress=3c:ec:ef:99:6d:4f

[Link]
Name=eth1

The problem after the update:
Now I can't get it to work anymore... I just performed a regular update via the Proxmox UI, and now the NIC with the IP address 192.168.20.201 has no connectivity at all; it can't be pinged, nor can it ping other devices. However, the other NIC with the IP address 192.168.50.201 is still accessible from the outside via ping. Unfortunately, I am unable to test if I can ping the outside world using this NIC because I don't know how to specify a NIC when using the ping command.

$: ip route


$: ip a


$: cat /etc/network/interfaces

 

[ChessMaster]

This may not be related, but...

After an update of my Proxmox box yesterday, I had no access to the GUI or the DMZ network. I found the network lights on the NIC would not light after boot-up of the system. It "appeared" by the action of the storage drive lights that the system was working, but I couldn't get into it via the network. The IPMI/direct connection worked fine and I could get to all the underlying Debian OS/files.

Long story short, and after a 3 hour diagnostic time, I found that (probably) during the upgrade, the NIC card name assignments got completely switched around. My 3 cards ended up with 3 different assignments (enp7s0, enp8s0, enp9s0, ended up as enp5s0, enp6s0, enp7s0). So the problem was that the new assignments found using the <ip a> command were different from the assignments in the /etc/network/interfaces file.

Anyway, the fix is easy if this ends up being your problem. Just <nano> (or vi, or whatever) through the IPMI/direct CLI into the /etc/network/interfaces file, and update your magically new NIC card assignments from your <ip a> list, into the Proxmox interfaces (example screenshots of the 2 screens you'll be working with are in the above post.)

I hope this helps someone...........

P.S. I just remembered that I also removed a NVME drive from the system just before I did the upgrade. I'm thinking that maybe there is a possibility that the PCIe assignments got moved around and that might be the cause of the moving NIC card names. So if you added/removed bus components on your motherboard, this might be the cause/fix too.

 

[ruben.urresti]

This may not be related, but...

After an update of my Proxmox box yesterday, I had no access to the GUI or the DMZ network. I found the network lights on the NIC would not light after boot-up of the system. It "appeared" by the action of the storage drive lights that the system was working, but I couldn't get into it via the network. The IPMI/direct connection worked fine and I could get to all the underlying Debian OS/files.

Long story short, and after a 3 hour diagnostic time, I found that (probably) during the upgrade, the NIC card name assignments got completely switched around. My 3 cards ended up with 3 different assignments (enp7s0, enp8s0, enp9s0, ended up as enp5s0, enp6s0, enp7s0). So the problem was that the new assignments found using the <ip a> command were different from the assignments in the /etc/network/interfaces file.

Anyway, the fix is easy if this ends up being your problem. Just <nano> (or vi, or whatever) through the IPMI/direct CLI into the /etc/network/interfaces file, and update your magically new NIC card assignments from your <ip a> list, into the Proxmox interfaces (example screenshots of the 2 screens you'll be working with are in the above post.)

I hope this helps someone...........

P.S. I just remembered that I also removed a NVME drive from the system just before I did the upgrade. I'm thinking that maybe there is a possibility that the PCIe assignments got moved around and that might be the cause of the moving NIC card names. So if you added/removed bus components on your motherboard, this might be the cause/fix too.

In my case, this was not the problem because the NIC names were already set to a fixed name using the .link file declarations I mentioned. I already used eth0 and eth1 before, and they still are named that way.