Proxmox server lost internet connection

[sammyke007]

Hi

I've been running a Proxmox server stable for months on a HP Elitedesk 800 G2.
I've updated Proxmox for th last time 2 days ago without any issues. Reboot went fine.
I'm on kernel 5.15.85-1-pve

Since this morning my ethernet connection dropped.
I connected the HP to a monitor and keyboard en I can see that it boots fine.

"ip a" still shows

192.168.1.5 for vmbr0 as configured, but I'm unable to ping my router or anything else.

The ethernet port on my HP is blinking orange however, very strange...

Any ideas please? Everything is down so no happy wife and kids... (PiHole, HASS, ...)

 

[leesteken]

Does ping -c1 192.168.1.1 work? Does ping -c1 1.1.1.1 work? Does ping -c1 www.google.com work?
Is the Proxmox host unreachable or can the host not reach the internet? I feel like the title and the first post suggest different things. Can you connect to the Proxmox host using https://192.168.1.5:8006/ from a computer on the local network? Maybe the initial IP address 192.168.1.5 came from the router via DHCP and it now conflicts with another device?
Did you try another ethernet cable? Is your router on the other end of the cable OK (an showing packet flow)?
Can you show the actual output of cat /etc/resolv.conf and ip r and ip a?

 

[sammyke007]

Cables are OK. I've moved the server to connect it to monitor and keyboard (and different ethernet cable).

ping -c1 192.168.1.1 = negative
ping -c1 1.1.1.1 = negative
ping -c1 www.google.com = negative

cat /etc/resolv.conf:
search lan
nameserver 192.168.1.1

ip r:
default via 192.168.1.1 dev vmbr0 proto kernel onlink
192.168.1.0/24 dev vmbr0 proto kernel scope link src 192.168.1.5

192.168.1.5 is reserved via MAC in my router and it has been like this for months.

 

[leesteken]

ping -c1 192.168.1.1 = negative

Looks like the connection between the system and the router is not working. Or your router does not respond to pings.

ping -c1 1.1.1.1 = negative

Either way, the routing to the internet is not working...
Are there blinking lights (green/orange/yellow) on the network ports of the system and the router?

cat /etc/resolv.conf:
search lan
nameserver 192.168.1.1

ip r:
default via 192.168.1.1 dev vmbr0 proto kernel onlink
192.168.1.0/24 dev vmbr0 proto kernel scope link src 192.168.1.5

192.168.1.5 is reserved via MAC in my router and it has been like this for months.

Maybe you have firewall rules that might have become active after a reboot that prevent outgoing connections?
Otherwise, it looks like it's a hardware problem or your router configuration is preventing the system to communicate.
A photo of the actual whole output of ip a might tell whether there is a physical connection or speed negotiation problem.

 

[sammyke007]

The Ethernet ports orange light is blinking, so I guess a hardware defect?

 

[leesteken]

The Ethernet ports orange light is blinking, so I guess a hardware defect?

The color of the lights depends on the device and the speeds it supports, so I don't know. Blinking suggest packet flow but hard to say what kind.
Looks like the hardware is working and established a 1Gbit connection between the system and the router as expected.
Can other devices on the local network ping the router successfully?
Can other devices reach the internet via your router? Or do you flow all internet traffic through a VM that might not be running?
It looks like only VM 100 and container 101 are running. Can you ping them from the Proxmox host?

 

[sammyke007]

VM100 and container 101 are indeed correct. I can't ping neither of them (192.168.1.6 for VM100 / 192.168.1.7 for Container101).
all other devices are working fine in the network (despites PiHole being down which runs in container 101)

 

[leesteken]

VM100 and container 101 are indeed correct. I can't ping neither of them (192.168.1.6 for VM100 / 192.168.1.7 for Container101).

Those are on a virtual network bridge, so that implies that the actual network hardware is not the problem.
EDIT: Maybe they don't respond to ping. Can you SSH into them?

all other devices are working fine in the network (despites PiHole being down which runs in container 101)

Sounds like the router is not the problem (unless it explicitly blocks all IPs coming from the Proxmox system, which is unlikely).

Sorry, but I have no idea why the virtual networking of Proxmox is not working after your reboot. Does systemctl --failed show anything?
Can you show a photo of /etc/network/interfaces to double check the configuration? EDIT: As this is something that typically becomes in effect after a reboot.

 

[sammyke007]

Sorry for the delayed answer...

Suddenly my Dell docking station also lost ethernet access. Somehow I was glad as it was a hardware network problem instead of a software Proxmox issue.

Rebooting my 2 switches did not help, but I saw a lot of kernel errors in my Asus router. I replugged LAN1 to LAN2 (my ethernet cable between switches and main Asus router) and BOOM everything was ok again.
A dying LAN port on my router seemed to be the issue. It's still strange as all my other wired devices kept working before the docking station lost ethernet, but it's fixed for now.

Tnx!