loosing network connectivity after setup / update / reboot

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Elleni

Renowned Member
Jul 6, 2020
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Hello community,

we have setup a dozen of pve so I got quite some experience. But on the last one I got puzzled as I setup from iso, do configure /etc/networking/intrfaces to our needs and everything works fine, so I configured the apt sources and updated the system. After a reboot i dont get any reply of the gateway anymore.

I setup twice now, once with the nic0/1 renaming option while setting up, and once without it. Bith times I initially got network connectivity until update/reboot.

What else can I provide so we can find the source of the problem to eliminate it? Thanks in advance for your support. As said - I was able to connect to webinterface via port 8006 and configure repo to temporary deactivate the enterprise repo till we buy subscription and activating the no-subscription repo and updating after new install.

ip addr still shows the fixed ip configured and the nic, vmbr0 and vm0.48@vmbr0 are all state UP - the ladder still configured with the static ip, but pinging the gateway in the same subnet does not work anymore thus no network connectivity...
 
Last edited:
Hi @Elleni,

The first step is to go through standard Linux network troubleshooting. Capture the network state when everything is functioning correctly, then capture it again when the network is "broken". Compare the two states.

Access the server via IPMI/BMC and perform basic checks:
  • Is the interface up?
  • Does ip a / ip link show anything different as compared to other nodes?
  • Are there errors in the boot log (dmesg, journalctl -b)?
  • Can connectivity be restored by restarting the networking service or cycling the interface?
You mentioned the gateway is not responding. What about other hosts on the same subnet?

Have you checked the switch side configuration/state ? :
  • Any port errors ?
  • VLAN misconfiguration?
  • MAC address table ok?
Inspect ARP behavior during failure. Are ARP requests leaving the host? Are replies coming back?

Keep in mind that Proxmox VE networking is native Debian. From the OS perspective, this is standard Linux networking. Any Linux network troubleshooting guide applies here.

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
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Port of nic vmbr0 and vmbr0.48 were all up, nothing seen in the logs - I was already ready to use an older iso for setup but I just wanted to show the problem to one of my colleagues - and all of a sudden connectivity was restored - no fuckin idea why. Last thing i had tried before that is to use the altname instead of the name showed in ip addr. However when that worked I changed the name back to the one showing with ip a and it continued to work so I let the thread here for a while but will ask for deletion after some hours as I dont see any value in my post.
 
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