[SOLVED] Ubuntu 22.04 LXC not connected to internet

rogierl · Feb 1, 2023

I have the following situation:

Proxmox 7.3.3 on the host, one network card available in the host. The host has ip address 192.168.1.100
I'm trying to run an LXC container (Ubuntu 22.04)
I applied the following networking settings for the LXC container:
- Name: eth0
- Bridge: vmbr0
- IP address: 192.168.1.13/24
- Gateway: 192.168.1.1
There are a couple VMs running as well, the have no problem with outgoing connections

I don't know how to solve this to be honest. Everything is filled in correctly, but still the LXC container doesn't have a connection to the internet. However, it can ping to my gateway, to the host and to other devices on the network. What could be wrong here?

A bit of debugging from within the LXC container

Code:

root@unifi:~# cat /etc/networks
# symbolic names for networks, see networks(5) for more information
link-local 169.254.0.0

root@unifi:~# ip a
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@if55: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 0e:34:6b:07:ff:90 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.1.13/24 brd 192.168.1.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::c34:6bff:fe07:ff90/64 scope link
       valid_lft forever preferred_lft forever

root@unifi:~# ip r
default via 192.168.1.1 dev eth0 proto static
192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.13

A bit of debugging from the Proxmox host

Code:

root@pve:~# pct config 113
arch: amd64
cores: 1
features: nesting=1
hostname: unifi
memory: 512
net0: name=eth0,bridge=vmbr0,firewall=1,gw=192.168.1.1,hwaddr=0E:34:6B:07:FF:90,ip=192.168.1.13/24,type=veth
ostype: ubuntu
rootfs: local-lvm:vm-113-disk-0,size=8G
swap: 512
unprivileged: 1


root@pve:~# pveversion -v
proxmox-ve: 7.3-1 (running kernel: 5.15.83-1-pve)
pve-manager: 7.3-3 (running version: 7.3-3/c3928077)
pve-kernel-helper: 7.3-2
pve-kernel-5.15: 7.3-1
pve-kernel-5.13: 7.1-9
pve-kernel-5.15.83-1-pve: 5.15.83-1
pve-kernel-5.15.74-1-pve: 5.15.74-1
pve-kernel-5.13.19-6-pve: 5.13.19-15
ceph-fuse: 15.2.13-pve1
corosync: 3.1.7-pve1
criu: 3.15-1+pve-1
glusterfs-client: 9.2-1
ifupdown2: 3.1.0-1+pmx3
ksm-control-daemon: 1.4-1
libjs-extjs: 7.0.0-1
libknet1: 1.24-pve2
libproxmox-acme-perl: 1.4.2
libproxmox-backup-qemu0: 1.3.1-1
libpve-access-control: 7.2-5
libpve-apiclient-perl: 3.2-1
libpve-common-perl: 7.3-1
libpve-guest-common-perl: 4.2-3
libpve-http-server-perl: 4.1-5
libpve-storage-perl: 7.3-1
libspice-server1: 0.14.3-2.1
lvm2: 2.03.11-2.1
lxc-pve: 5.0.0-3
lxcfs: 4.0.12-pve1
novnc-pve: 1.3.0-3
proxmox-backup-client: 2.3.1-1
proxmox-backup-file-restore: 2.3.1-1
proxmox-mini-journalreader: 1.3-1
proxmox-offline-mirror-helper: 0.5.0-1
proxmox-widget-toolkit: 3.5.3
pve-cluster: 7.3-1
pve-container: 4.4-2
pve-docs: 7.3-1
pve-edk2-firmware: 3.20220526-1
pve-firewall: 4.2-7
pve-firmware: 3.6-2
pve-ha-manager: 3.5.1
pve-i18n: 2.8-1
pve-qemu-kvm: 7.1.0-4
pve-xtermjs: 4.16.0-1
qemu-server: 7.3-2
smartmontools: 7.2-pve3
spiceterm: 3.2-2
swtpm: 0.8.0~bpo11+2
vncterm: 1.7-1
zfsutils-linux: 2.1.7-pve3
root@pve:~#



[/CODE}

Moayad · Feb 1, 2023

Hi,

Maybe IP 192.168.1.13 is already reserved or used on another VM/CT? Can you please post the working CT configurations pct config <CTID>? And the following commands from a working CT?

Bash:

ip r
ip a
cat /etc/resolv.conf

rogierl · Feb 1, 2023

Moayad said:
Hi,

Maybe IP 192.168.1.13 is already reserved or used on another VM/CT? Can you please post the working CT configurations pct config <CTID>? And the following commands from a working CT?

Bash:

ip r ip a cat /etc/resolv.conf

Thanks for your (quick!!!) reply, @Moayad !
Here is the output:

Code:

rogierl@services [~]$ ip r
default via 192.168.1.1 dev ens18 proto static
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown
172.18.0.0/16 dev br-c982adcafdc5 proto kernel scope link src 172.18.0.1
192.168.1.0/24 dev ens18 proto kernel scope link src 192.168.1.102


rogierl@services [~]$ ip a
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: ens18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 82:73:ce:63:c6:c5 brd ff:ff:ff:ff:ff:ff
    altname enp0s18
    inet 192.168.1.102/24 brd 192.168.1.255 scope global ens18
       valid_lft forever preferred_lft forever
    inet6 2a02:a46b:1e24:1:8073:ceff:fe63:c6c5/64 scope global dynamic mngtmpaddr noprefixroute
       valid_lft 7145sec preferred_lft 3545sec
    inet6 fe80::8073:ceff:fe63:c6c5/64 scope link
       valid_lft forever preferred_lft forever
3: tailscale0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1280 qdisc fq_codel state UNKNOWN group default qlen 500
    link/none
    inet 100.80.24.113/32 scope global tailscale0
       valid_lft forever preferred_lft forever
    inet6 fd7a:115c:a1e0:ab12:4843:cd96:6250:1871/128 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::5927:c4f2:fdac:7562/64 scope link stable-privacy
       valid_lft forever preferred_lft forever
4: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
    link/ether 02:42:3b:7f:6a:e2 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
5: br-c982adcafdc5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
    link/ether 02:42:9f:36:8e:54 brd ff:ff:ff:ff:ff:ff
    inet 172.18.0.1/16 brd 172.18.255.255 scope global br-c982adcafdc5
       valid_lft forever preferred_lft forever
    inet6 fe80::42:9fff:fe36:8e54/64 scope link
       valid_lft forever preferred_lft forever


rogierl@services [~]$ cat /etc/resolv.conf
# This is /run/systemd/resolve/stub-resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.

nameserver 127.0.0.53
options edns0 trust-ad
search taileea20.ts.net
[/CODE}

rogierl · Feb 5, 2023

Oh my god... my bad

. I filled in the ip address in the DNS "domain" section.

Japinto1 · Feb 15, 2025

rogierl said:
Oh my god... my bad . I filled in the ip address in the DNS "domain" section.

View attachment 46432

I'm embarrassed to admit that I spent a couple of hours trying to find this setting in the container OS, just to find out that it was part of the container settings in PVE

Search

Search

[SOLVED] Ubuntu 22.04 LXC not connected to internet

rogierl

Member

Moayad

Proxmox Staff Member

rogierl

Member

rogierl

Member

Japinto1

New Member

We value your privacy