Network Problems after upgrading to 22.04.1

Question

After upgrading from 20.04 to 22.04.1, I have no network access either via ethernet or wifi.

I can bring both interfaces up via command line or gui and they show as connected and also pick up an ip address over dhcp.

However, I can't ping anything (by address) - not even the loopback address.

The firewall is disabled. The routing table matches one of my other machines which is working fine.

Any ideas to debug this one gratefully received!

Possibly related to Broken network configuration after upgrade to 22.04

Network Manager Status

● NetworkManager.service - Network Manager
     Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2022-08-17 18:30:16 BST; 1 day 19h ago
       Docs: man:NetworkManager(8)
   Main PID: 1582 (NetworkManager)
      Tasks: 3 (limit: 16572)
     Memory: 11.3M
        CPU: 5.092s
     CGroup: /system.slice/NetworkManager.service
             └─1582 /usr/sbin/NetworkManager --no-daemon
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.8481] dhcp4 (enp34s0): activation: beginning transaction (timeout in 45 seconds)
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.8654] dhcp4 (enp34s0): state changed new lease, address=192.168.0.225
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.8679] device (enp34s0): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'managed')
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.9135] device (enp34s0): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'managed')
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.9140] device (enp34s0): state change: secondaries -> activated (reason 'none', sys-iface-state: 'managed')
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.9146] manager: NetworkManager state is now CONNECTED_LOCAL
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.9150] manager: NetworkManager state is now CONNECTED_SITE
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.9151] policy: set 'netplan-enp34s0' (enp34s0) as default for IPv4 routing and DNS
Aug 19 13:54:43 deepthought NetworkManager[1582]: <info>  [1660913683.9158] device (enp34s0): Activation: successful, device activated.
Aug 19 13:54:53 deepthought NetworkManager[1582]: <info>  [1660913693.3834] agent-manager: agent[438527325db3dfb9,:1.82/org.gnome.Shell.NetworkAgent/1000]: agent registered

resolved

systemd-resolved also looks unhappy although I'm way off being able to use names right now.

● systemd-resolved.service - Network Name Resolution
     Loaded: loaded (/lib/systemd/system/systemd-resolved.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2022-08-17 18:30:15 BST; 1 day 19h ago
       Docs: man:systemd-resolved.service(8)
             man:org.freedesktop.resolve1(5)
             https://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers
             https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients
   Main PID: 1278 (systemd-resolve)
     Status: "Processing requests..."
      Tasks: 1 (limit: 16572)
     Memory: 9.4M
        CPU: 517ms
     CGroup: /system.slice/systemd-resolved.service
             └─1278 /lib/systemd/systemd-resolved
Aug 19 14:19:16 deepthought systemd-resolved[1278]: Using degraded feature set UDP instead of TCP for DNS server 192.168.0.2.
Aug 19 14:19:26 deepthought systemd-resolved[1278]: Using degraded feature set TCP instead of UDP for DNS server 192.168.0.2.
Aug 19 14:19:57 deepthought systemd-resolved[1278]: Using degraded feature set UDP instead of TCP for DNS server 192.168.0.2.
Aug 19 14:20:08 deepthought systemd-resolved[1278]: Using degraded feature set TCP instead of UDP for DNS server 192.168.0.2.
Aug 19 14:23:35 deepthought systemd-resolved[1278]: Using degraded feature set UDP instead of TCP for DNS server 192.168.0.2.
Aug 19 14:23:45 deepthought systemd-resolved[1278]: Using degraded feature set TCP instead of UDP for DNS server 192.168.0.2.
Aug 19 14:24:16 deepthought systemd-resolved[1278]: Using degraded feature set UDP instead of TCP for DNS server 192.168.0.2.
Aug 19 14:24:26 deepthought systemd-resolved[1278]: Using degraded feature set TCP instead of UDP for DNS server 192.168.0.2.
Aug 19 14:24:57 deepthought systemd-resolved[1278]: Using degraded feature set UDP instead of TCP for DNS server 192.168.0.2.
Aug 19 14:25:08 deepthought systemd-resolved[1278]: Using degraded feature set TCP instead of UDP for DNS server 192.168.0.2.

Jie Geng · Answer 1 · 2022-08-24T13:36:20.340

I spent one day one this, tried many methods. Finally, I found it was due to the firewall. I disabled the firewall, it connected to the internet right after.
But, I haven't figure out which parts in the firewall setting caused this.

sudo ufw disable

－－－－－－－－－－－－－－－－

The problem I had: After upgrade from 20.04 to 22.04, the ethernet connection doesn't have internet!

ping 127.0.0.1 not work, 100% loss
ping 192.168.68.1 router, not work, 100% loss
but the local network work, other devices can access the net-shared harddrives
I can ssh to the pc from other device, and even from outside the home network openvpn works from outside the home network

score 1 · Answer 2 · answered Dec 18 '22 at 18:25

Following Jie Geng option with ufw, found the real issue

There is a conflict between netfilter-persistent package and ufw.

You must remove netfilter-persistent

sudo apt purge netfilter-persistent

And then reboot the system.

You won't need to stop the ufw service if you do this.

In fact, when you run the ufw check requirements testing script, you will find that it will be saying that netfilter-persistent could be conflicting. Idea found in Launchpad bug tracker.

sudo /usr/share/ufw/check-requirements

score 0 · Answer 3 · answered Oct 08 '24 at 17:57

Check this article.

    To do so, run the following commands:
sudo ufw allow in on <network_bridge>
sudo ufw route allow in on <network_bridge>
sudo ufw route allow out on <network_bridge>
For example:
sudo ufw allow in on lxdbr0
sudo ufw route allow in on lxdbr0
sudo ufw route allow out on lxdbr0

Network Problems after upgrading to 22.04.1

Network Manager Status

resolved

3 Answers3

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