Proxmox CTs and VMs lost network connectivity

bradw

12/30/22, 9:37 AM

I have a a Proxmox setup on my home network which was working fine up until yesterday when the network connections in all virtual machines and containers stopped working. I believe this was after updating the kernel but I can't be sure. Could also be due to installing docker on the host.

I've tried rebooting server + router, creating fresh containers and disabled firewall at all levels (DC, server, CT/VM) to no avail which leads me to believe it's an issue with the host.

I can't reach anything to/from the containers. Host networking seems fine - it can reach anything else on the local network and internet. Only access I have to the containers is via the Proxmox console.

ip route (host)

default via 192.168.1.1 dev vmbr0 proto kernel onlink 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown 
192.168.1.0/24 dev vmbr0 proto kernel scope link src 192.168.1.2

pct config 113 (host)

arch: amd64
cores: 8
features: nesting=1
hostname: test
memory: 5120
net0: name=eth0,bridge=vmbr0,firewall=1,gw=192.168.1.1,hwaddr=D6:78:ED:73:E2:68,ip=192.168.1.23/32,type=veth
ostype: ubuntu
rootfs: local-lvm:vm-113-disk-0,size=8G
swap: 512
unprivileged: 1

ip route (container)

default via 192.168.1.1 dev eth0 proto static 
192.168.1.1 dev eth0 proto static scope link

ip addr (container)

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0@if50: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether d6:78:ed:73:e2:68 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.1.23/32 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::d478:edff:fe73:e268/64 scope link 
       valid_lft forever preferred_lft forever

359

0 + 2

networking

virtualization

linux-networking

proxmox

Nikita Kipriyanov

12/30/22, 9:49 AM

Most probably it is because you installed docker to the host. Why? Don't do that. As I remember, Proxmox documentation says explicitely Docker on the host is not supported and if you need it you must deploy a VM and install it there.

Tom Yan

12/30/22, 10:52 AM

Hmm, I think you should use `/24` instead of `/32` (for `ip=` of `net0:`)?

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Proxmox CTs and VMs lost network connectivity

TH: Proxmox CT และ VM สูญเสียการเชื่อมต่อเครือข่าย

RO: CT-urile și VM-urile Proxmox și-au pierdut conectivitatea la rețea

RU: Proxmox CT и виртуальные машины потеряли сетевое подключение

VI: Proxmox CT và VM bị mất kết nối mạng

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